Pierre-Yves David <pierre-yves.david@logilab.fr> [Fri, 20 Jan 2012 18:45:29 +0100] rev 15952
mq-safety: don't apply safety on non-outgoing changeset
When mq changeset are secret, they don't appear in outgoing and won't be
pushed. So it's not necessary to abort the push.
The checkpush call is protected by lock to prevent race on phase.