offer-muc-stream-tube: use exec_tube_test
offer-muc-stream-tube: use exec_tube_test

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