Fix from SF patch 565085: copy._reduction doesn't __setstate__.

Straightforward fix.  Will backport to 2.2.  If there's ever a new 2.1
release, this could be backported there too (since it's an issue with
anything that's got both a __reduce__ and a __setstate__).

Lib/copy.py

@@ -301,6 +301,9 @@ def _reconstruct(x, info, deep, memo=None):
     if state:
         if deep:
             state = deepcopy(state, memo)
+        if hasattr(y, '__setstate__'):
+            y.__setstate__(state)
+        else:
             y.__dict__.update(state)
     return y