Don't enable twisted tests if we don't have at least python 2.5.
Don't enable twisted tests if we don't have at least python 2.5.

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