Fix use connection after free

[git-hulk]

This bug was reported by the address sanitizer which we want to integrate into Kvrocks ci workflow, after investigating the error and found it's imported by #430. The solution was thatclose_cb should be ran before removing the connection.

==4657==ERROR: AddressSanitizer: heap-use-after-free on address 0x614000010070 at pc 0x00010bf183cb bp 0x70000f255700 sp 0x70000f2556f8
READ of size 8 at 0x614000010070 thread T88
    #0 0x10bf183ca in std::__1::__function::__value_func<void (int)>::operator bool() const functional:1927
    #1 0x10bf04eb4 in std::__1::function<void (int)>::operator bool() const functional:2412
    #2 0x10bf04e5f in Redis::Connection::Close() redis_connection.cc:50
    #3 0x10bf093a7 in Redis::Connection::OnEvent(bufferevent*, short, void*) redis_connection.cc:96
    #4 0x10d1316d9 in bufferevent_run_deferred_callbacks_unlocked bufferevent.c:225
    #5 0x10d142b00 in event_process_active_single_queue event.c:1703
    #6 0x10d13d440 in event_process_active event.c:1789
    #7 0x10d13c37a in event_base_loop event.c:2012
    #8 0x10d13c056 in event_base_dispatch event.c:1823
    #9 0x10bf2c181 in Worker::Run(std::__1::__thread_id) worker.cc:131
    #10 0x10bf46b9e in WorkerThread::Start()::$_0::operator()() const worker.cc:332
    #11 0x10bf4699c in decltype(std::__1::forward<WorkerThread::Start()::$_0>(fp)()) std::__1::__invoke<WorkerThread::Start()::$_0>(WorkerThread::Start()::$_0&&) type_traits:3694
    #12 0x10bf46934 in void std::__1::__thread_execute<std::__1::unique_ptr<std::__1::__thread_struct, std::__1::default_delete<std::__1::__thread_struct> >, WorkerThread::Start()::$_0>(std::__1::tuple<std::__1::unique_ptr<std::__1::__thread_struct, std::__1::default_delete<std::__1::__thread_struct> >, WorkerThread::Start()::$_0>&, std::__1::__tuple_indices<>) thread:286
    #13 0x10bf45a72 in void* std::__1::__thread_proxy<std::__1::tuple<std::__1::unique_ptr<std::__1::__thread_struct, std::__1::default_delete<std::__1::__thread_struct> >, WorkerThread::Start()::$_0> >(void*) thread:297
    #14 0x7ff8038d74f3 in _pthread_start+0x7c (libsystem_pthread.dylib:x86_64+0x64f3)
    #15 0x7ff8038d300e in thread_start+0xe (libsystem_pthread.dylib:x86_64+0x200e)

0x614000010070 is located 48 bytes inside of 432-byte region [0x614000010040,0x6140000101f0)
freed by thread T88 here:
    #0 0x1110c2d1d in wrap__ZdlPv+0x7d (libclang_rt.asan_osx_dynamic.dylib:x86_64h+0x50d1d)
    #1 0x10bf2dfa1 in Worker::FreeConnection(Redis::Connection*) worker.cc:199
    #2 0x10bf04e52 in Redis::Connection::Close() redis_connection.cc:49
    #3 0x10bf093a7 in Redis::Connection::OnEvent(bufferevent*, short, void*) redis_connection.cc:96
    #4 0x10d1316d9 in bufferevent_run_deferred_callbacks_unlocked bufferevent.c:225
    #5 0x10d142b00 in event_process_active_single_queue event.c:1703
    #6 0x10d13d440 in event_process_active event.c:1789
    #7 0x10d13c37a in event_base_loop event.c:2012
    #8 0x10d13c056 in event_base_dispatch event.c:1823
    #9 0x10bf2c181 in Worker::Run(std::__1::__thread_id) worker.cc:131
    #10 0x10bf46b9e in WorkerThread::Start()::$_0::operator()() const worker.cc:332
    #11 0x10bf4699c in decltype(std::__1::forward<WorkerThread::Start()::$_0>(fp)()) std::__1::__invoke<WorkerThread::Start()::$_0>(WorkerThread::Start()::$_0&&) type_traits:3694
    #12 0x10bf46934 in void std::__1::__thread_execute<std::__1::unique_ptr<std::__1::__thread_struct, std::__1::default_delete<std::__1::__thread_struct> >, WorkerThread::Start()::$_0>(std::__1::tuple<std::__1::unique_ptr<std::__1::__thread_struct, std::__1::default_delete<std::__1::__thread_struct> >, WorkerThread::Start()::$_0>&, std::__1::__tuple_indices<>) thread:286
    #13 0x10bf45a72 in void* std::__1::__thread_proxy<std::__1::tuple<std::__1::unique_ptr<std::__1::__thread_struct, std::__1::default_delete<std::__1::__thread_struct> >, WorkerThread::Start()::$_0> >(void*) thread:297
    #14 0x7ff8038d74f3 in _pthread_start+0x7c (libsystem_pthread.dylib:x86_64+0x64f3)
    #15 0x7ff8038d300e in thread_start+0xe (libsystem_pthread.dylib:x86_64+0x200e)

previously allocated by thread T88 here:
    #0 0x1110c28fd in wrap__Znwm+0x7d (libclang_rt.asan_osx_dynamic.dylib:x86_64h+0x508fd)
    #1 0x10bf2a9ff in Worker::newConnection(evconnlistener*, int, sockaddr*, int, void*) worker.cc:84
    #2 0x10d14cf2a in listener_read_cb listener.c:424
    #3 0x10d14335f in event_persist_closure event.c:1629
    #4 0x10d1429d8 in event_process_active_single_queue event.c:1688
    #5 0x10d13d440 in event_process_active event.c:1789
    #6 0x10d13c37a in event_base_loop event.c:2012
    #7 0x10d13c056 in event_base_dispatch event.c:1823
    #8 0x10bf2c181 in Worker::Run(std::__1::__thread_id) worker.cc:131
    #9 0x10bf46b9e in WorkerThread::Start()::$_0::operator()() const worker.cc:332
    #10 0x10bf4699c in decltype(std::__1::forward<WorkerThread::Start()::$_0>(fp)()) std::__1::__invoke<WorkerThread::Start()::$_0>(WorkerThread::Start()::$_0&&) type_traits:3694
    #11 0x10bf46934 in void std::__1::__thread_execute<std::__1::unique_ptr<std::__1::__thread_struct, std::__1::default_delete<std::__1::__thread_struct> >, WorkerThread::Start()::$_0>(std::__1::tuple<std::__1::unique_ptr<std::__1::__thread_struct, std::__1::default_delete<std::__1::__thread_struct> >, WorkerThread::Start()::$_0>&, std::__1::__tuple_indices<>) thread:286
    #12 0x10bf45a72 in void* std::__1::__thread_proxy<std::__1::tuple<std::__1::unique_ptr<std::__1::__thread_struct, std::__1::default_delete<std::__1::__thread_struct> >, WorkerThread::Start()::$_0> >(void*) thread:297
    #13 0x7ff8038d74f3 in _pthread_start+0x7c (libsystem_pthread.dylib:x86_64+0x64f3)
    #14 0x7ff8038d300e in thread_start+0xe (libsystem_pthread.dylib:x86_64+0x200e)

Thread T88 created by T0 here:
    #0 0x1110b04fc in wrap_pthread_create+0x5c (libclang_rt.asan_osx_dynamic.dylib:x86_64h+0x3e4fc)
    #1 0x10bf4593b in std::__1::__libcpp_thread_create(_opaque_pthread_t**, void* (*)(void*), void*) __threading_support:510
    #2 0x10bf454d2 in std::__1::thread::thread<WorkerThread::Start()::$_0, void>(WorkerThread::Start()::$_0&&) thread:313
    #3 0x10bf3394c in std::__1::thread::thread<WorkerThread::Start()::$_0, void>(WorkerThread::Start()::$_0&&) thread:305
    #4 0x10bf334df in WorkerThread::Start() worker.cc:330
    #5 0x10c5d003a in Server::Start() server.cc:77
    #6 0x10bf4a63b in main main.cc:327
    #7 0x11d05f4fd in start+0x1cd (dyld:x86_64+0x54fd)

SUMMARY: AddressSanitizer: heap-use-after-free functional:1927 in std::__1::__function::__value_func<void (int)>::operator bool() const
Shadow bytes around the buggy address:
  0x1c2800001fb0: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
  0x1c2800001fc0: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
  0x1c2800001fd0: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
  0x1c2800001fe0: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
  0x1c2800001ff0: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
=>0x1c2800002000: fa fa fa fa fa fa fa fa fd fd fd fd fd fd[fd]fd
  0x1c2800002010: fd fd fd fd fd fd fd fd fd fd fd fd fd fd fd fd
  0x1c2800002020: fd fd fd fd fd fd fd fd fd fd fd fd fd fd fd fd
  0x1c2800002030: fd fd fd fd fd fd fd fd fd fd fd fd fd fd fa fa
  0x1c2800002040: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
  0x1c2800002050: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
Shadow byte legend (one shadow byte represents 8 application bytes):
  Addressable:           00
  Partially addressable: 01 02 03 04 05 06 07 
  Heap left redzone:       fa
  Freed heap region:       fd
  Stack left redzone:      f1
  Stack mid redzone:       f2
  Stack right redzone:     f3
  Stack after return:      f5
  Stack use after scope:   f8
  Global redzone:          f9
  Global init order:       f6
  Poisoned by user:        f7
  Container overflow:      fc
  Array cookie:            ac
  Intra object redzone:    bb
  ASan internal:           fe
  Left alloca redzone:     ca
  Right alloca redzone:    cb
  Shadow gap:              cc
==4657==ABORTING