message: mission: fix timeout notification
  This was broken in the previous fix. The activity state would always be
  NONE if it is changed before it is used/checked.
diff: @@ -1407,10 +1407,8 @@ void MissionImpl::process_timeout()
  _mission_data.mutex.lock();
  if (_mission_data.retries++ > MAX_RETRIES) {
  _mission_data.retries = 0;
  - {
  +
  std::lock_guard<std::mutex> lock(_activity.mutex);
  - _activity.state = Activity::State::NONE;
  - }
  LogWarn() << "Mission handling timed out.";
  if (_activity.state == Activity::State::GET_MISSION_LIST ||
  _activity.state == Activity::State::GET_MISSION_REQUEST) {
  @@ -1426,6 +1424,8 @@ void MissionImpl::process_timeout()
  LogWarn() << "Clearing mission timed out...";
  report_mission_result(_mission_data.result_callback, Mission::Result::TIMEOUT);
  }
  +
  + _activity.state = Activity::State::NONE;
  _mission_data.mutex.unlock();
  } else {
  