Change logging level AUDIT to INFO

According to the latest revision of the logging guidelines message
of type AUDIT should be moved to INFO.

The latest revision is available at https://review.openstack.org/#/c/91446/
at the moment.

Change-Id: I2d86fa634f6424b0bb862319b9ae40d3f3b1ec7a
Merge "Change logging level AUDIT to INFO"