Fixes #15721 (again) via a minor tweak to avoid unexpected behaviour of copy() which caused a range of test failures

git-svn-id: http://code.djangoproject.com/svn/django/trunk@16044 bcc190cf-cafb-0310-a4f2-bffc1f526a37

django/template/context.py

@@ -92,7 +92,7 @@ class Context(BaseContext):
         super(Context, self).__init__(dict_)
 
     def __copy__(self):
-        duplicate = copy(super(Context, self))
+        duplicate = super(Context, self).__copy__()
         duplicate.render_context = copy(self.render_context)
         return duplicate