revert to marcos 0 instead of NULL - sorry for commiting that

git-svn-id: http://svn.osgeo.org/qgis/trunk/qgis@15415 c8812cc2-4d05-0410-92ff-de0c093fc19c

Author: macho

src/app/qgisapp.cpp

@@ -626,7 +626,7 @@ QgisApp::~QgisApp()
   removeAnnotationItems();
 
   // cancel request for FileOpen events
-  QgsApplication::setFileOpenEventReceiver( NULL );
+  QgsApplication::setFileOpenEventReceiver( 0 );
 
   // delete map layer registry and provider registry
   QgsApplication::exitQgis();