[mpris] Move to freedesktop.org

[Alex Merry]

We've moved MPRIS over to freedesktop.org now.  You should all be 
subscribed to the new email list 
(http://lists.freedesktop.org/mailman/listinfo/mpris) unless you chose 
not to be on the visible subscriber list for this list.

You should have received an email with various details about the move at 
the new list.  If not, you need to make sure emails from the new list 
are not being treated as spam.  The email is available in the archive of 
the new list (see above).

Alex