debug level logs should not be translated

According to the OpenStack translation policy available at
https://wiki.openstack.org/wiki/LoggingStandards debug messages
should not be translated. Like mentioned in several changes in
Nova by garyk this is to help prioritize log translation.

This patch adds a new hacking check - N319 - that ensures all
debug log messages don't have translations.

Change-Id: I9dd958b904671a7eb95883026e14684469dc52d5
Closes-Bug: #1317847
Merge "debug level logs should not be translated"