[YSQL] DCHECK failure in RefCountedThreadSafeBase::Release : !in_dtor_ in PgLibPqTest.CatalogManagerMapsTest

[mbautin]

Jira Link: DB-4824
./yb_build.sh --cxx-test pgwrapper_pg_libpq-test --gtest_filter PgLibPqTest.CatalogManagerMapsTest -n 100

Stack trace (after forcing a segfault at this assertion failure and symbolizing with gdb):

#0  0x00007fb83496fee1 in yb::client::YBClient::Data::SetMasterServerProxyAsync(yb::client::YBClient*, std::chrono::time_point<yb::CoarseMonoClock, std::chrono::duration<long, std::ratio<1l, 1000000000l> > >, bool, yb::Callback<void (yb::Status const&)> const&) (this=this@entry=0x7fb7fc000920, client=client@entry=0x7fb7fc000900, deadline=...,
    skip_resolution=skip_resolution@entry=false, cb=...) at ../../src/yb/client/client-internal.cc:1469
1469	    (**leader_master_rpc_).SendRpc();
warning: File "/opt/yb-build/brew/linuxbrew-20181203T161736v2-3ba4c2ed9b0587040949a4a9a95b576f520bae/Cellar/gcc/5.5.0_4/lib/libstdc++.so.6.0.21-gdb.py" auto-loading has been declined by your `auto-load safe-path' set to "$debugdir:$datadir/auto-load:/usr/bin/mono-gdb.py".
(gdb) where
#0  0x00007fb83496fee1 in yb::client::YBClient::Data::SetMasterServerProxyAsync(yb::client::YBClient*, std::chrono::time_point<yb::CoarseMonoClock, std::chrono::duration<long, std::ratio<1l, 1000000000l> > >, bool, yb::Callback<void (yb::Status const&)> const&) (this=this@entry=0x7fb7fc000920, client=client@entry=0x7fb7fc000900, deadline=...,
    skip_resolution=skip_resolution@entry=false, cb=...) at ../../src/yb/client/client-internal.cc:1469
#1  0x00007fb8349707b7 in yb::client::YBClient::Data::SetMasterServerProxy (this=this@entry=0x7fb7fc000920, client=client@entry=0x7fb7fc000900, deadline=..., skip_resolution=skip_resolution@entry=false) at ../../src/yb/client/client-internal.cc:1400
#2  0x00007fb83498affd in yb::client::YBClient::Data::SyncLeaderMasterRpc<yb::master::GetYsqlCatalogConfigRequestPB, yb::master::GetYsqlCatalogConfigResponsePB>(std::chrono::time_point<yb::CoarseMonoClock, std::chrono::duration<long, std::ratio<1l, 1000000000l> > >, yb::client::YBClient*, yb::master::GetYsqlCatalogConfigRequestPB const&, yb::master::GetYsqlCatalogConfigResponsePB*, int*, char const*, std::function<yb::Status (yb::master::MasterServiceProxy*, yb::master::GetYsqlCatalogConfigRequestPB const&, yb::master::GetYsqlCatalogConfigResponsePB*, yb::rpc::RpcController*)> const&) (this=0x7fb7fc000920, deadline=..., client=client@entry=0x7fb7fc000900, req=...,
    resp=resp@entry=0x7ffc823e9c50, num_attempts=0x0, func_name=0x7fb834a15a75 "GetYsqlCatalogConfig", func=...) at ../../src/yb/client/client-internal.cc:196
#3  0x00007fb83495cc89 in yb::client::YBClient::GetYsqlCatalogMasterVersion (this=0x7fb7fc000900, ysql_catalog_version=ysql_catalog_version@entry=0x7ffc823e9d58) at ../../src/yb/client/client.cc:624
#4  0x00007fb838f5081b in yb::pggate::PgSession::GetCatalogMasterVersion (this=<optimized out>, version=version@entry=0x7ffc823e9d58) at ../../src/yb/yql/pggate/pg_session.cc:169
#5  0x00007fb838f45efd in yb::pggate::PgApiImpl::GetCatalogMasterVersion (this=<optimized out>, pg_session=<optimized out>, version=version@entry=0x7ffc823e9d58) at ../../src/yb/yql/pggate/pggate.cc:348
#6  0x00007fb838f42073 in yb::pggate::YBCPgGetCatalogMasterVersion (pg_session=<optimized out>, version=version@entry=0x7ffc823e9d58) at ../../src/yb/yql/pggate/ybc_pggate.cc:174
#7  0x00000000007da230 in YBRefreshCache () at ../../../../../../src/postgres/src/backend/tcop/postgres.c:3703
#8  0x00000000007de82f in YBCheckSharedCatalogCacheVersion () at ../../../../../../src/postgres/src/backend/tcop/postgres.c:3855
#9  PostgresMain (argc=<optimized out>, argv=argv@entry=0x26ea610, dbname=0x26ea5e8 "postgres", username=0x26ea5c0 "postgres") at ../../../../../../src/postgres/src/backend/tcop/postgres.c:4646
#10 0x000000000075d787 in BackendRun (port=0x271e200) at ../../../../../../src/postgres/src/backend/postmaster/postmaster.c:4398
#11 BackendStartup (port=0x271e200) at ../../../../../../src/postgres/src/backend/postmaster/postmaster.c:4064
#12 ServerLoop () at ../../../../../../src/postgres/src/backend/postmaster/postmaster.c:1724
#13 PostmasterMain (argc=argc@entry=19, argv=argv@entry=0x26e95d0) at ../../../../../../src/postgres/src/backend/postmaster/postmaster.c:1387
#14 0x00000000006bfef1 in PostgresServerProcessMain (argc=19, argv=0x26e95d0) at ../../../../../../src/postgres/src/backend/main/main.c:234
#15 0x00000000006bff8d in main ()