JingleFactory: store WockySession as well as Porter
JingleFactory: store WockySession as well as Porter

This makes ::porter-available the only place in jingle-factory.c which
uses the connection non-trivially, laying the ground for removing it…

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