Files with no code must be left completely empty

As per OpenStack licensing guide lines [1]:
[H104] Files with no code shouldn't contain any license header nor
comments, and must be left completely empty.

[1] http://docs.openstack.org/developer/hacking/#openstack-licensing

Change-Id: I2df3d796aabbd2d283520b207bee3a80e663ecb4

tests/unit/openstack/common/__init__.py

@@ -1,14 +0,0 @@
-# Copyright (c) 2013 Rackspace, Inc.
-#
-# 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.