tests/test-abort-checkin.out

fix test-mq-eol under --pure (mimic diffhelper.c behaviour)

bug discovered by apycot (apycot.hg-scm.org)

error: pretxncommit.nocommits hook failed: no commits allowed
transaction abort!
rollback completed
abort: no commits allowed
error: pretxncommit.nocommits hook failed: no commits allowed
transaction abort!
rollback completed
abort: no commits allowed