gabble_file_transfer_channel_constructor: add a debug msg telling some info about the FT
gabble_file_transfer_channel_constructor: add a debug msg telling some info about the FT

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