[rhythmbox] metadata: fix compilation with older versions of GStreamer

[Jonathan Matthew <jmatthew src gnome org>]

commit f57dfa9e31748b742c0d8a1c4f107d6fef487063
Author: Jonathan Matthew <jonathan d14n org>
Date:   Sun Feb 21 10:16:50 2010 +1000

    metadata: fix compilation with older versions of GStreamer
    
    gst_message_unref only recently became a function.  Passing it as a
    function pointer doesn't work with versions where it was a macro, so we
    can't do that yet.

 metadata/rb-metadata-gst.c |    5 ++++-
 1 files changed, 4 insertions(+), 1 deletions(-)
---
diff --git a/metadata/rb-metadata-gst.c b/metadata/rb-metadata-gst.c
index b4ee1d4..6d7eb75 100644
--- a/metadata/rb-metadata-gst.c
+++ b/metadata/rb-metadata-gst.c
@@ -99,7 +99,10 @@ rb_metadata_reset (RBMetaData *md)
 	md->priv->has_non_audio = FALSE;
 	md->priv->has_video = FALSE;
 	if (md->priv->missing_plugins != NULL) {
-		g_slist_foreach (md->priv->missing_plugins, (GFunc) gst_message_unref, NULL);
+		GSList *t;
+		for (t = md->priv->missing_plugins; t != NULL; t = t->next) {
+			gst_message_unref (GST_MESSAGE (t->data));
+		}
 		g_slist_free (md->priv->missing_plugins);
 		md->priv->missing_plugins = NULL;
 	}