[rygel] core: Explain AlbumArt.add_resource() in a comment

[Zeeshan Ali Khattak <zeeshanak src gnome org>]

commit c20b0dc28f4d8c3643c6a275586a4989ca6830e9
Author: Zeeshan Ali (Khattak) <zeeshanak gnome org>
Date:   Mon Jul 19 19:12:32 2010 +0300

    core: Explain AlbumArt.add_resource() in a comment
    
    Add a comment explaining why AlbumArt.add_resource() doesn't really add
    do what the name suggests.

 src/rygel/rygel-album-art.vala |    3 +++
 1 files changed, 3 insertions(+), 0 deletions(-)
---
diff --git a/src/rygel/rygel-album-art.vala b/src/rygel/rygel-album-art.vala
index 6466fe7..39023c9 100644
--- a/src/rygel/rygel-album-art.vala
+++ b/src/rygel/rygel-album-art.vala
@@ -27,6 +27,9 @@ public class Rygel.AlbumArt : Thumbnail {
         base ();
     }
 
+    /* This doesn't really add a resource. Blame UPnP/DLNA for treating
+     * thumbnails and album-art differently for no apparent reason.
+     */
     internal override DIDLLiteResource? add_resource (DIDLLiteItem didl_item,
                                                       string       protocol) {
         didl_item.album_art = this.uri;