Enable hacking check H104

* [H104] Files with no code shouldn’t contain any license
         header nor comments, and must be left completely empty.

Change-Id: Ic02858615833b516fd2c68a859146c8e018ae8e1

designateclient/tests/__init__.py

@@ -1,13 +0,0 @@
-# -*- coding: utf-8 -*-
-
-# Licensed under the Apache License, Version 2.0 (the "License"); you may
-# not use this file except in compliance with the License. You may obtain
-# a copy of the License at
-#
-#      http://www.apache.org/licenses/LICENSE-2.0
-#
-# Unless required by applicable law or agreed to in writing, software
-# distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
-# WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
-# License for the specific language governing permissions and limitations
-# under the License.

tox.ini

@@ -34,7 +34,6 @@ commands = {posargs}
 
 [flake8]
 # ignored flake8 codes:
-# H104 file contains nothing more than comments
 # H302 import only modules
 # H402 one line docstring needs punctuation
 # H404 multi line docstring should start with a summary
@@ -42,6 +41,6 @@ commands = {posargs}
 # H904 Wrap long lines in parentheses instead of a backslash
 # See designate for other ignored codes that may apply here
 
-ignore = H104,H302,H402,H404,H405,H904
+ignore = H302,H402,H404,H405,H904
 builtins = _
 exclude = .venv,.git,.tox,dist,doc,*openstack/common*,*lib/python*,*egg,build,tools