Minor fix for Python 2.x compatibility.

Author: mdboom

Diff for: lib/matplotlib/testing/decorators.py

@@ -49,7 +49,7 @@ def failer(*args, **kwargs):
         return nose.tools.make_decorator(f)(failer)
     return known_fail_decorator
 
-class CleanupTest:
+class CleanupTest(object):
     @classmethod
     def setup_class(cls):
         cls.original_units_registry = matplotlib.units.registry.copy()