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: I639624cbe64749085654b32ac85596fdae577230
Switch over to mox3

mox3 is a Python 3.x compatible drop-in and allows
to continue with the porting effort to Python 3.x with
minimal code changes.

Closes-Bug: #1283482
Change-Id: Ib052f1b87e312481e4c7c8d775ece94f53e7106b
Merge "debug level logs should not be translated"
Merge "Switch over to mox3"