Should run all pyflakes and pep8 checks

[Clint Byrum]

Right now only a small subset of pyflakes is used on the code. We should follow other code bases' examples and use flake8 with as few disabled rules as possible.

[Pavlo Shchelokovskyy (pshchelo)]

Just to note:

Right now we already have only 3 style checks from oslo.hacking disabled in our tox.ini.

There is also a blueprint reduce-flake8-ignored-rules for it.

[Pavlo Shchelokovskyy (pshchelo)]

Actually there are only two left [1] already:
- check that there is no full stop in commit title
- check for proper multiline docstring formatting

Those are not code style per se, so I propose to close this bug already

[1] https://github.com/openstack/heat/blob/master/tox.ini#L51

[Steve Baker (steve-stevebaker)]

We're down to ignore = H404,H405

I think this can be closed off.