make logformat more similar to oslo

make the logformat actually match what we're used to reading in
the other logs, especially including the levels.

Because the logging fixture doesn't include the oslo logging
context processor, we are limited in what we can do here. A good
follow on would be to make a fixture which does understand oslo
logging processing so we could get request_id in the logs.

Change-Id: Ibb95aebd2df714fae331df13ad7789d6341af265
Updated from global requirements

Change-Id: If54fdc67edc8775584b0636632f5c4ab7aec6ed0
Merge "make logformat more similar to oslo"
Merge branch 'master' of https://github.com/openstack/tempest