Merge commit '8025945a62d16ef078299ad5903081f250d762ed' into felipec

These changes can be merged with some adjustments.
That is, only conditionally prefer some newer API, but otherwise
prefer current code paths, which have been tried and tested for a
long time through various version (both python and hg).

git-remote-hg

@@ -424,6 +424,10 @@ def export_files(files):
     return final
 
 def get_filechanges(repo, ctx, parent):
+    if hasattr(parent, 'status'):
+        stat = parent.status(ctx)
+        return stat.modified + stat.added, stat.removed
+
     modified = set()
     added = set()
     removed = set()