Add a new qlog alias for queue log.

Needed with mq.secret enabled because it assigns mq patches the "secret"
phase, which causes them to be ignored by hg outgoing. Which is awesome,
but it means that I can no longer review unpushed changes with outgoing
when they are still managed by mq. Using qlog lets me see my queue
changesets. In theory. outgoing should still show me the unpushed
changesets that are released from mq control.