[gnome-control-center] a11y: Silence a compiler warning

[Matthias Clasen <matthiasc src gnome org>]

commit b289fab6c8d044f6f6aa924a708a7cc9dabd2824
Author: Matthias Clasen <mclasen redhat com>
Date:   Sun Dec 1 10:38:56 2013 -0500

    a11y: Silence a compiler warning
    
    build.gnome.org now records warnings, and this came up.

 panels/universal-access/cc-ua-panel.c |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)
---
diff --git a/panels/universal-access/cc-ua-panel.c b/panels/universal-access/cc-ua-panel.c
index 8dab686..ed4c842 100644
--- a/panels/universal-access/cc-ua-panel.c
+++ b/panels/universal-access/cc-ua-panel.c
@@ -117,7 +117,7 @@ cc_ua_panel_dispose (GObject *object)
   CcUaPanelPrivate *priv = CC_UA_PANEL (object)->priv;
 
   g_clear_object (&priv->builder);
-  g_slist_free_full (priv->toplevels, gtk_widget_destroy);
+  g_slist_free_full (priv->toplevels, (GDestroyNotify)gtk_widget_destroy);
   priv->toplevels = NULL;
 
   g_clear_object (&priv->wm_settings);