Use debug level logging during unit tests

When unit tests fail we need to debug, so we should have debug level logging on.
We use fixtures FakeLogger during testing, to  enable debug logging pass
in log level as a parameter.
http://bazaar.launchpad.net/~python-fixtures/python-fixtures/trunk/view/head:/lib/fixtures/_fixtures/logger.py#L68

Change-Id: I70790aa39c0774726de71e5fa5751c45e7e34ffd
Merge "Use debug level logging during unit tests"