[flake8] Enable extra, optional hacking checks

Update test-requirements.txt to use latest version of:
    * hacking

Enable the following off-by-default checks:
    * [H203] Use assertIs(Not)None to check for None.
    * [H204] Use assert(Not)Equal to check for equality.
    * [H205] Use assert(Greater|Less)(Equal) for comparison.
    * [H210] Require ‘autospec’, ‘spec’, or ‘spec_set’ in
             mock.patch/mock.patch.object calls
    * [H904] Delay string interpolations at logging calls.

Made necessary unit test changes to work with these checks.

Change-Id: I9db3445caa2883563fd7271d6bf0b24800e06c01
6 files changed