addressing-util: Refactor gabble_uri_for_handle.
addressing-util: Refactor gabble_uri_for_handle.

mlundblad/telepathy-gabble,Ziemin/telepathy-gabble,mlundblad/telepathy-gabble,Ziemin/telepathy-gabble,mlundblad/telepathy-gabble,Ziemin/telepathy-gabble,Ziemin/telepathy-gabble