add LLAgent::removeRegionChangedCallback

indra/newview/llagent.cpp

@@ -981,6 +981,10 @@ boost::signals2::connection LLAgent::addRegionChangedCallback(region_changed_cal
 	return mRegionChangedSignal.connect(cb);
 }
 
+void LLAgent::removeRegionChangedCallback(boost::signals2::connection callback)
+{
+	mRegionChangedSignal.disconnect(callback);
+}
 
 //-----------------------------------------------------------------------------
 // inPrelude()

indra/newview/llagent.h

@@ -273,6 +273,7 @@ class LLAgent : public LLOldEvents::LLObservable
 	 */
 	typedef boost::function<void()> region_changed_callback_t;
 	boost::signals2::connection     addRegionChangedCallback(region_changed_callback_t);
+	void                            removeRegionChangedCallback(boost::signals2::connection callback);
 
   private:
 	LLViewerRegion	*mRegionp;