graft-state: save --base in graft's state, fixing bug with graft --continue
Without this change, running graft --continue after grafting a merge commit using --base
(and encountering conflicts) will output "skipping ungraftable merge revision" even though
we specified a base in the initial graft command.
Graft's improve behaviour is reflected in test-graft.t.
Differential Revision: https://phab.mercurial-scm.org/D8578
Issue351: mq: qrefresh can create extra revlog entry
$ echo "[extensions]" >> $HGRCPATH
$ echo "mq=" >> $HGRCPATH
$ hg init
$ hg qinit
$ echo b > b
$ hg ci -A -m foo
adding b
$ echo cc > b
$ hg qnew -f foo.diff
$ echo b > b
$ hg qrefresh
$ hg debugindex b
rev linkrev nodeid p1 p2
0 0 1e88685f5dde 000000000000 000000000000