Sort directory contents in test before assertion

Should fix recent test failures, but I can't replicate failure on my
computer, so it's not clear that it's fixed.

IPython/html/services/contents/tests/test_manager.py

@@ -188,7 +188,7 b' class TestContentsManager(TestCase):'
         
         dir_model = cm.get_model(path)
         self.assertEqual(
-            dir_model['content'],
+            sorted(dir_model['content'], key=lambda x: x['name']),
             [symlink_model, file_model],
         )