Don't call set_application() in gtk_window_realize

This call has no effect and with the newly-added restrictions it's
violating the set-application-after-realized rule.

https://bugzilla.gnome.org/show_bug.cgi?id=668203

gtk/gtkwindow.c

@@ -5330,8 +5330,6 @@ gtk_window_realize (GtkWidget *widget)
     }
 #endif
 
-  gtk_window_set_application (window, gtk_window_get_application (window));
-
   /* Icons */
   gtk_window_realize_icon (window);