Add hacking checks

There have been a handful of changes recently to fix stylistic bugs
in the unit tests (example: If41a7). The changes themselves were fine,
but there are two problems:

1) The stylistic changes they made were not listed in HACKING.rst
2) They were one-time changes; the rules that were violated will
   continue to be violated.

This change updates HACKING.rst to include a few of the stylistic
rules that have been fixed recently, and adds checks to ensure that
they will be enforced going forward. This is based on nova's hacking
checks.

Change-Id: Ic115342605c472f3a5d255aa570ecb60175ca087
Add test for no_translate_debug_logs hacking check

Adds a test for this hacking check. Also update the code (G319).

Change-Id: I91996b94166f0e69ee4f5fc0b704118d59bfe841
Merge "Add hacking checks"
Merge "Add test for no_translate_debug_logs hacking check"