Apply Octavia hacking checks to the tempest plugin

Currently we are not applying the custom hacking checks we use in
Octavia to the octavia-tempest-plugin. This leads to style issues
sneaking into the plugin.
This patch copies the same checks from Octavia (for simpler
management) into octavia-tempest-plugin and resolves some of the
existing style violations.

Change-Id: Ic103d8bededfec77ec0034d7c167ac1e49954a5c
6 files changed