message: core: unlock/return if an unknown ack arrives
diff: @@ -213,6 +213,12 @@ void MAVLinkCommands::receive_command_ack(mavlink_message_t message)
  &_timeout_cookie);
  _work_queue.return_front();
  break;
  +
  + default:
  + LogWarn() << "Received unknown ack.";
  + _state_mutex.unlock();
  + _work_queue.return_front();
  + break;
  }
  }
  