localrepo: don't refresh filecache entries that aren't in __dict__

We call invalidate to remove properties from __dict__ because they're
possibly outdated and we'd like to check for a new version. Next time
the property is accessed the filecache mechanism checks the current stat
info with the one recorded at the last time the property was read, if
they're different it recreates the property.

Previously we refreshed the stat info on all properties in the filecache
when the lock is released, including properties that are missing from
__dict__. This is a problem because:

  l = repo.lock()
  repo.P          # stat info S for P is recorded in _filecache
  <changes are made to repo.P indirectly, e.g. underlying file is replaced>
                  # P's new stat info = S'
  l.release()     # filecache refreshes, records S' as P's stat info

At this point our filecache contains P with stat info S', but P's
version is from S, which is outdated.

The above happens during _rollback and strip. Currently we're wiping the
filecache and forcing everything to reload from scratch which works but
isn't the right solution.

mercurial/localrepo.py

@@ -1015,7 +1015,7 class localrepository(object):
             if hasunfilteredcache(self, '_phasecache'):
                 self._phasecache.write()
             for k, ce in self._filecache.items():
-                if k == 'dirstate':
+                if k == 'dirstate' or k not in self.__dict__:
                     continue
                 ce.refresh()