gabble_media_channel_request_streams: lazily create a session if necessary (also simplify error handling)
gabble_media_channel_request_streams: lazily create a session if necessary (also simplify error handling)


20080430153959-53eee-dd8be2453c6882a1880e7cb8b27d75eb60562889.gz

community-ssu/telepathy-gabble,community-ssu/telepathy-gabble,mlundblad/telepathy-gabble,mlundblad/telepathy-gabble,Ziemin/telepathy-gabble,mlundblad/telepathy-gabble,community-ssu/telepathy-gabble,Ziemin/telepathy-gabble,Ziemin/telepathy-gabble,jku/telepathy-gabble,community-ssu/telepathy-gabble,jku/telepathy-gabble,Ziemin/telepathy-gabble,jku/telepathy-gabble