Remove the __unicode__ method from exceptions.  Allows unicode() to be called
on exception classes.  Would require introducing a tp_unicode slot to make it
work otherwise.

Fixes bug #1551432 and will be backported.
diff --git a/Lib/test/test_pep352.py b/Lib/test/test_pep352.py
index 251e0be..b2322b0 100644
--- a/Lib/test/test_pep352.py
+++ b/Lib/test/test_pep352.py
@@ -15,8 +15,7 @@
         self.failUnless(issubclass(Exception, object))
 
     def verify_instance_interface(self, ins):
-        for attr in ("args", "message", "__str__", "__unicode__", "__repr__",
-                "__getitem__"):
+        for attr in ("args", "message", "__str__", "__repr__", "__getitem__"):
             self.failUnless(hasattr(ins, attr), "%s missing %s attribute" %
                     (ins.__class__.__name__, attr))