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.

Change-Id: Ia38a426a1a3154302b19f2dc603487175566c863
Closes-Bug: #1318384