The smoke test that ran the CLI command "acl delete" with a null entity_ref was failing with an exception in the cliff library. This test is invalid, since the CLI parser would not accept this command without an entity_ref. This test failed more gracefully with cliff 2.3.0, but in 2.4.0 cliff throws an exception that causes this test to start failing. Change-Id: If91d4966eff77dad7c8569e309134dc540edc258