Last time we did this was nearly 4 years ago; drag ourselves into
something approaching the present. Address a few new pyflakes issues
that seem reasonable to enforce:
E275 missing whitespace after keyword
E231 missing whitespace after ','
E721 do not compare types, for exact checks use `is` / `is not`,
for instance checks use `isinstance()`
Main motivator is that the old hacking kept us on an old version
of flake8 et al., which no longer work with newer Pythons.
Change-Id: I54b46349fabb9776dcadc6def1cfb961c123aaa0
76ca11773e