Use hacking from test-requirements

Just like all other OpenStack projects use the hacking version from
test-requirements. Also install all dependencies before running flake8
so we can do import analysis such has H302. Turn off H302 until the
existing are resolved.

Change-Id: I6c5a983025406c1ebd4b537b95c6e8ce97849898
Merge "Use hacking from test-requirements"