[rygel] server: Avoid circular reference

[Jens Georg <jensgeorg src gnome org>]

commit 4e584c97fbcff6018a8264c49171698c76278d01
Author: Jens Georg <mail jensge org>
Date:   Sat Jan 31 01:56:12 2015 +0100

    server: Avoid circular reference
    
    Signed-off-by: Jens Georg <mail jensge org>
    
    https://bugzilla.gnome.org/show_bug.cgi?id=736365

 src/librygel-server/rygel-content-directory.vala |    5 ++---
 src/librygel-server/rygel-media-container.vala   |    4 ++++
 2 files changed, 6 insertions(+), 3 deletions(-)
---
diff --git a/src/librygel-server/rygel-content-directory.vala 
b/src/librygel-server/rygel-content-directory.vala
index e87f480..20bf25a 100644
--- a/src/librygel-server/rygel-content-directory.vala
+++ b/src/librygel-server/rygel-content-directory.vala
@@ -95,9 +95,8 @@ public class Rygel.ContentDirectory: Service {
         this.root_container = plugin.root_container;
         this.http_server = new HTTPServer (this, plugin.name);
 
-        this.updated_containers = new ArrayList<MediaContainer> ((a, b) => {
-                return a.id == b.id;
-            });
+        this.updated_containers = new ArrayList<MediaContainer>
+                                        (MediaContainer.equal_func);
         this.active_imports = new ArrayList<ImportResource> ();
         this.finished_imports = new ArrayList<ImportResource> ();
 
diff --git a/src/librygel-server/rygel-media-container.vala b/src/librygel-server/rygel-media-container.vala
index a5a6514..a0b6f49 100644
--- a/src/librygel-server/rygel-media-container.vala
+++ b/src/librygel-server/rygel-media-container.vala
@@ -75,6 +75,10 @@ public abstract class Rygel.MediaContainer : MediaObject {
                                               "+upnp:originalTrackNumber," +
                                               "+dc:title";
 
+    public static bool equal_func (MediaContainer a, MediaContainer b) {
+        return a.id == b.id;
+    }
+
     /**
      * The container_updated signal is emitted if the subtree unter this
      * container has been modified. The object parameter is set to