auditvfs: forward options property from nested vfs

This was breaking my ability to use treemanifests in bundlerepos, and
was deeply mysterious. We should probably just make the options
property a formal part of the vfs API, and make it a required
construction parameter. Sadly, I don't have time to dive into that
refactor right now.

mercurial/scmutil.py

@@ -638,6 +638,14 b' class auditvfs(object):'
     def mustaudit(self, onoff):
         self.vfs.mustaudit = onoff
 
+    @property
+    def options(self):
+        return self.vfs.options
+
+    @options.setter
+    def options(self, value):
+        self.vfs.options = value
+
 class filtervfs(abstractvfs, auditvfs):
     '''Wrapper vfs for filtering filenames with a function.'''