match: avoid rust fast path if the matcher was tampered with
Otherwise the fast path does not respect the modifications made
by the extension (concretely largefiles, but other extensions can
start using that too)
Issue351: mq: qrefresh can create extra revlog entry
$ echo "[extensions]" >> $HGRCPATH
$ echo "mq=" >> $HGRCPATH
$ hg init repo
$ cd repo
$ 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-nodeid p2-nodeid
0 0 1e88685f5dde 000000000000 000000000000