message: mission: remove unused variable
diff: @@ -66,8 +66,6 @@ private:
  SEND_COMMAND
  } _activity = Activity::NONE;
  - int _last_set_current_mavlink_mission_item = -1;
  -
  int _last_current_mavlink_mission_item;
  int _last_reached_mavlink_mission_item;
  