gtkplacessidebar: fix signal marshal

We were using __VOID for the SHOW_OTHER_LOCATION signal that
uses flags named SHOR_OTHER_LOCATION_WITH_FLAGS.
However, if a signal uses flags the marshal needs to use __FLAGS.

This patch addresses this using VOID__FLAGS as the marshaler parameter.

Thanks to Jan Steffens for pointing this out.

https://bugzilla.gnome.org/show_bug.cgi?id=770550

gtk/gtkplacessidebar.c

@@ -4391,7 +4391,7 @@ gtk_places_sidebar_class_init (GtkPlacesSidebarClass *class)
                         G_SIGNAL_RUN_FIRST,
                         G_STRUCT_OFFSET (GtkPlacesSidebarClass, show_other_locations_with_flags),
                         NULL, NULL,
-                        _gtk_marshal_VOID__VOID,
+                        _gtk_marshal_VOID__FLAGS,
                         G_TYPE_NONE, 1,
                         GTK_TYPE_PLACES_OPEN_FLAGS);