repoview: allow methods on the proxy class to be replaced

It doesn't seem to be a common idiom for repo instances, but the status() method
is replaced in largefiles' purge() override.  Since __setattr__ is implemented
in repoview to setattr() on the unfiltered repo, the replacement method wouldn't
get called unless it was invoked with the unfiltered repo, because the filtered
repo remains unchanged.

Since this doesn't seem to be commonly used, I didn't bother to filter out
methods that perhaps shouldn't be replaced, such as changelog().

mercurial/repoview.py

@@ -6,6 +6,7 b''
 # This software may be used and distributed according to the terms of the
 # GNU General Public License version 2 or any later version.
 
+import types
 import copy
 import error
 import phases
@@ -310,6 +311,10 b' class repoview(object):'
         return getattr(self._unfilteredrepo, attr)
 
     def __setattr__(self, attr, value):
+        # Allow method replacement on filtered repos, like status() in
+        # largefiles' purge override
+        if type(value) == types.FunctionType:
+            object.__setattr__(self, attr, value)
         return setattr(self._unfilteredrepo, attr, value)
 
     def __delattr__(self, attr):