localrepo: refresh filecache stats only if transaction finished successfully
If commit is aborted by pretxncommit hook, in-memory changelog and manifest
have entries that would be added. So they must be discarded on invalidate().
But the mechanism introduced by
a710936c3037 doesn't handle this case well.
It tries to mitigate the penalty of invalidate() by marking in-memory cache
as "clean" on unlock assuming that they are identical to the stored data.
But this assumption is wrong if stored data are rolled back by tr.abort().
This patch moves the hook to post-close action so that it will never be
triggered on abort.
This bug was originally reported to thg, which is only reproducible in
command-server process on unix, evolve disabled.
https://bitbucket.org/tortoisehg/thg/issues/4285/