Enforce log hints in neutron.services.firewall

This change enforces log hints use and removes debug level log
translation, modifications are validated through a hacking rule.

Validate that hacking rules apply to directories:
    - neutron/services/firewall

Change-Id: Ie3f75fe207652cbd800cef067a89a819696d1f3a
Partial-bug: #1320867
Merge "Enforce log hints in neutron.services.firewall"