Undo patches in teardown before attempting to delete files

notebook/tests/launchnotebook.py

@@ -178,9 +178,9 @@ class NotebookTestBase(TestCase):
     def teardown_class(cls):
         cls.notebook.stop()
         cls.wait_until_dead()
-        cls.tmp_dir.cleanup()
         cls.env_patch.stop()
         cls.path_patch.stop()
+        cls.tmp_dir.cleanup()
         # cleanup global zmq Context, to ensure we aren't leaving dangling sockets
         def cleanup_zmq():
             zmq.Context.instance().term()