histedit: pass multiple nodes to strip (BC)
Previously, histedit.cleanupnode pass root nodes one by one. Since
repair.strip takes multiple nodes and can handle them just fine, pass all
strip roots at once.
This is BC because the number of strip backup files may change from N to 1.
$ 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