proxy-vfs: also proxy the `audit` attribute
In the previous changeset, we had to do a little dance to access the useful
`audit` attribute. We now provide a proper accessors to it.
We don't update the code in `perf.py` because it has to remain compatible with
older version of Mercurial. This will just be nicer in the future.
$ echo "[extensions]" >> $HGRCPATH
$ echo "mq=" >> $HGRCPATH
$ hg init repo
$ cd repo
$ echo 'base' > base
$ hg ci -Ambase
adding base
$ hg qnew -mmqbase mqbase
$ hg qsave
$ hg qrestore 2
restoring status: hg patches saved state