AP_Camera: make AP_Camera::control() return bool for picture trigger

this allows a picture to be logged if it is requested

libraries/AP_Camera/AP_Camera.cpp

@@ -210,11 +210,14 @@ void AP_Camera::configure(float shooting_mode, float shutter_speed, float apertu
     GCS_MAVLINK::send_to_components(&msg);
 }
 
-void AP_Camera::control(float session, float zoom_pos, float zoom_step, float focus_lock, float shooting_cmd, float cmd_id)
+bool AP_Camera::control(float session, float zoom_pos, float zoom_step, float focus_lock, float shooting_cmd, float cmd_id)
 {
+    bool ret = false;
+    
     // take picture
     if (is_equal(shooting_cmd,1.0f)) {
         trigger_pic(false);
+        ret = true;
     }
 
     mavlink_message_t msg;
@@ -234,6 +237,7 @@ void AP_Camera::control(float session, float zoom_pos, float zoom_step, float fo
 
     // send to all components
     GCS_MAVLINK::send_to_components(&msg);
+    return ret;
 }
 
 /*

libraries/AP_Camera/AP_Camera.h

@@ -56,7 +56,8 @@ public:
 
     // Command processing
     void            configure(float shooting_mode, float shutter_speed, float aperture, float ISO, float exposure_type, float cmd_id, float engine_cutoff_time);
-    void            control(float session, float zoom_pos, float zoom_step, float focus_lock, float shooting_cmd, float cmd_id);
+    // handle camera control. Return true if picture was triggered
+    bool            control(float session, float zoom_pos, float zoom_step, float focus_lock, float shooting_cmd, float cmd_id);
 
     // set camera trigger distance in a mission
     void            set_trigger_distance(uint32_t distance_m) { _trigg_dist.set(distance_m); }