conn-olpc: revoke_invitations: ignore fake activities aka the ones without ID
conn-olpc: revoke_invitations: ignore fake activities aka the ones without ID

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