Test-requirements.txt: Bump Hacking to 0.12
Test-requirements.txt: Bump Hacking to 0.12

We already pass all the checks.

Change-Id: I9af2eb26dfb1ecf296753dcfc505768d534929ea

dtroyer/python-openstackclient,openstack/python-openstackclient,dtroyer/python-openstackclient,openstack/python-openstackclient