Add TRIPLEO_DEBUG var for enabling debug logging

If we would like to run any jobs with debug logging enabled (which we
would like to for the HA job) then we need a way for to specify this.

Depends on tripleo-incubator change:
I3f267f3d6290fddb40d80b1c889bade8980ddb43

Change-Id: Icf36094605eeaf6923ea1a9ab60386eda11730e9
Merge "Add TRIPLEO_DEBUG var for enabling debug logging"