Fixed freezing of GAL canvas if user chooses Cancel in the on close dialog.

pcbnew/pcbframe.cpp

@@ -591,7 +591,6 @@ void PCB_EDIT_FRAME::OnQuit( wxCommandEvent& event )
 void PCB_EDIT_FRAME::OnCloseWindow( wxCloseEvent& Event )
 {
     m_canvas->SetAbortRequest( true );
-    GetGalCanvas()->StopDrawing();
 
     if( GetScreen()->IsModify() )
     {
@@ -615,6 +614,8 @@ void PCB_EDIT_FRAME::OnCloseWindow( wxCloseEvent& Event )
         }
     }
 
+    GetGalCanvas()->StopDrawing();
+
     // Delete the auto save file if it exists.
     wxFileName fn = GetBoard()->GetFileName();