convert: fix syncing deletes from p2 merge commit
Recently we fixed converting merges to correctly sync changes from p2. We missed
the case of deletes though (so p2 deleted a file that p1 had not yet deleted,
and the file does not belong to the source).
The fix is to detect when p2 doesn't have the file, so we just sync it as a
delete to p1 in the merge.
Updated the test, and verified it failed before the fix.
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 offset length ..... linkrev nodeid p1 p2 (re)
0 0 3 ..... 0 1e88685f5dde 000000000000 000000000000 (re)