revlog-split: make sure the self._indexfile attribut is reset (issue6811)
Before this change, after a transaction committing a file split, a revlog
object would have its `self._indexfile` attribute desynchronised from the
actual file storing the data. If that same object is reused (as we do for the
manifest during clone bundles), this lead to the data being writting in the
wrong location and the repository to go corrupt.
We not properly reset the attribut when applicable and everything is back in
working order.
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