revert: don't assume ignored files will be returned in the unknown list
That's just an artifact of the current implementation, and I'll change
that soon.
Bonus points:
- we don't care about the unknown list at all
- we don't print an extra message if we try to revert a removed file
that is not present in the target revision
adding a
1 files updated, 0 files merged, 0 files removed, 0 files unresolved
adding b
pushing to ../a
abort: could not lock repository ../a: Permission denied