Prevent erroneous socket closure

src/server.cpp

@@ -3262,6 +3262,7 @@ void initMasterInfo(redisMaster *master)
     master->repl_state = REPL_STATE_NONE;
     master->repl_down_since = 0; /* Never connected, repl is down since EVER. */
     master->mvccLastSync = 0;
+    master->repl_transfer_fd = -1;
 }
 
 void initServerConfig(void) {