If 'noqa' is specified all hacking checks are disabled.
It is better to ignore specific rules explicitly rather than
ignoring all. The recent flake8 supports this [1].
[1] http://flake8.pycqa.org/en/stable/user/ignoring-errors.html
Change-Id: I0f2a0cccf459c5a353f777a2be352c0faa8b18e0