Core/IPC: Fixed bnet & world servers getting stuck on shutdown after having communicated at any point

src/server/ipc/ZMQTask.cpp

@@ -44,6 +44,7 @@ void ZMQTask::Start()
 void ZMQTask::End()
 {
     _thread->join();
+    _poller->remove(*_inproc);
     _inproc->close();
     HandleClose();
 }