proposed change to test-requirements breaks py34

Patch https://review.openstack.org/#/c/278720 attempts to change test-requirements import of mock to be conditional for only 3.2 and lower. But the mock namespace in py34 is "unittest.mock" not just "mock" So this patch breaks on failing imports:

2016-02-10 23:35:34.138 | Failed to import test module: tests.unit.formatters.test_text
2016-02-10 23:35:34.138 | Traceback (most recent call last):
2016-02-10 23:35:34.138 | File "/home/jenkins/workspace/gate-bandit-python34/.tox/py34/lib/python3.4/site-packages/unittest2/loader.py", line 456, in _find_test_path
2016-02-10 23:35:34.138 | module = self._get_module_from_name(name)
2016-02-10 23:35:34.138 | File "/home/jenkins/workspace/gate-bandit-python34/.tox/py34/lib/python3.4/site-packages/unittest2/loader.py", line 395, in _get_module_from_name
2016-02-10 23:35:34.138 | __import__(name)
2016-02-10 23:35:34.139 | File "/home/jenkins/workspace/gate-bandit-python34/tests/unit/formatters/test_text.py", line 20, in <module>
2016-02-10 23:35:34.139 | import mock
2016-02-10 23:35:34.139 | ImportError: No module named 'mock'