Moblin-Media prevents gstreamer-dbus-media-service from playing *.m4a audio

Even though the current moblin stack contains all the needed gstreamer plug-ins for playing MPEG-4 audio using m4a files, the moblin-media engine management code wrongly assumes that the gstreamer based media service doesn't support the format.

To test this, copy any m4a files (like music that iTunes rips from your CD collection) to /home/ume/media/audio/, start (or restart) moblin-media and click on the Music tab. The player will not list any of the m4a files via the thumbnail view, and if you switch to list-view and you select one of the m4a files then you get an error message.