[rygel] core: Correct XML namespace for author & artist

[Jens Georg <jensgeorg src gnome org>]

commit c619fee9b1c0a3213bc50a0b464acaf999571b74
Author: Jens Georg <mail jensge org>
Date:   Sat May 5 09:08:32 2012 +0200

    core: Correct XML namespace for author & artist
    
    We were using dc: for some reason, but it*s upnp:

 src/rygel/rygel-media-objects.vala |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)
---
diff --git a/src/rygel/rygel-media-objects.vala b/src/rygel/rygel-media-objects.vala
index 9cf657c..e91316c 100644
--- a/src/rygel/rygel-media-objects.vala
+++ b/src/rygel/rygel-media-objects.vala
@@ -28,7 +28,7 @@ using GUPnP;
  */
 public class Rygel.MediaObjects : ArrayList<MediaObject> {
     public const string SORT_CAPS = "@id,@parentID,dc:title,upnp:class," +
-                                    "dc:artist,dc:author,upnp:album," +
+                                    "upnp:artist,upnp:author,upnp:album," +
                                     "dc:date,upnp:originalTrackNumber";
 
     public override Gee.List<MediaObject>? slice (int start, int stop) {