don't need the nose make_decorator function any more.

pizzathief · pizzathief · commit 09e559a3c49e · 2016-01-21T12:09:06.000+11:00
diff --git a/lib/matplotlib/testing/decorators.py b/lib/matplotlib/testing/decorators.py
@@ -410,5 +410,5 @@ def backend_switcher(*args, **kwargs):
                 plt.switch_backend(prev_backend)
             return result
 
-        return nose.tools.make_decorator(func)(backend_switcher)
+        return func(backend_switcher)
     return switch_backend_decorator
