src: remove unnecessary req_wrap_obj

The req_wrap_obj is only used in one place which is setting up the
arguments for the MakeCallback call. Removing it to simplify the code
somewhat.

PR-URL: nodejs#10942
Reviewed-By: Anna Henningsen <anna@addaleax.net>
Reviewed-By: Ben Noordhuis <info@bnoordhuis.nl>
Reviewed-By: Colin Ihrig <cjihrig@gmail.com>
Reviewed-By: James M Snell <jasnell@gmail.com>
Reviewed-By: Brian White <mscdex@mscdex.net>

src/connection_wrap.cc

@@ -99,11 +99,10 @@ void ConnectionWrap<WrapType, UVType>::AfterConnect(uv_connect_t* req,
     writable = uv_is_writable(req->handle) != 0;
   }
 
-  Local<Object> req_wrap_obj = req_wrap->object();
   Local<Value> argv[5] = {
     Integer::New(env->isolate(), status),
     wrap->object(),
-    req_wrap_obj,
+    req_wrap->object(),
     Boolean::New(env->isolate(), readable),
     Boolean::New(env->isolate(), writable)
   };