camera_feedback: remove unused class member & call orb_unsubscribe()

src/modules/camera_feedback/camera_feedback.cpp

@@ -220,7 +220,10 @@ CameraFeedback::task_main()
 
 	}
 
-	PX4_INFO("Exiting.");
+	orb_unsubscribe(_trigger_sub);
+	orb_unsubscribe(_gpos_sub);
+	orb_unsubscribe(_att_sub);
+
 	_main_task = -1;
 
 }

src/modules/camera_feedback/camera_feedback.hpp

@@ -98,7 +98,6 @@ private:
 	int			_main_task;				/**< handle for task */
 
 	int			_trigger_sub;
-	int			_lpos_sub;
 	int			_gpos_sub;
 	int			_att_sub;