Initialize clutter-gst for the user panel

Otherwise, we get an error out of libcheese, complaining about
gstreamer not being initialized.

configure.ac

@@ -117,6 +117,7 @@ PKG_CHECK_MODULES(UNIVERSAL_ACCESS_PANEL, $COMMON_MODULES gsettings-desktop-sche
 PKG_CHECK_MODULES(USER_ACCOUNTS_PANEL, $COMMON_MODULES dbus-glib-1
                   polkit-gobject-1 >= $POLKIT_REQUIRED_VERSION
                   gnome-desktop-3.0
+                  clutter-gst-1.0
                   gdk-pixbuf-2.0 >= $GDKPIXBUF_REQUIRED_VERSION)
 PKG_CHECK_MODULES(WACOM_PANEL, $COMMON_MODULES
                   gnome-settings-daemon >= $GSD_REQUIRED_VERSION

panels/user-accounts/um-user-module.c

@@ -23,6 +23,7 @@
 
 #include "um-user-panel.h"
 
+#include <clutter-gst/clutter-gst.h>
 #include <glib/gi18n.h>
 
 void
@@ -31,6 +32,8 @@ g_io_module_load (GIOModule *module)
   bindtextdomain (GETTEXT_PACKAGE, GNOMELOCALEDIR);
   bind_textdomain_codeset (GETTEXT_PACKAGE, "UTF-8");
 
+  clutter_gst_init (NULL, NULL);
+
   /* register the panel */
   um_user_panel_register (module);
 }