import: --no-commit should update .hg/last-message.txt
The patch parser goes through all of that trouble extracting the
commit message from the patch file. It seems such a waste not to
use it.
$ echo "[extensions]" >> $HGRCPATH
$ echo "mq=" >> $HGRCPATH
$ hg init
$ echo 'base' > base
$ hg ci -Ambase
adding base
$ hg qnew -mmqbase mqbase
$ hg qsave
$ hg qrestore 2
restoring status: hg patches saved state