Improve default logging configuration

By default, a number of serious exceptions were not being
logged. Adding a logger for 'django'-related logs resolves this.

Also:
 - Add loggers for missing clients and django_openstack_auth
 - Add a default level for individual loggers (what makes it out to
   the log file remains determined by the handler configuration)

Change-Id: Id3478ac8ec79f22c19ef66e747f3701f98a36611
Closes-Bug: #1236423
Merge "Improve default logging configuration"
Add keystoneclient CredentialsManager if missing

The keystone v3 client doesn't include the 'ec2' manager, even
though the EC2 API is included in the default pipeline.

This commit creates the ec2 manager manually if it's missing
(and necessary). It uses the same call that the client itself
should have used.

Change-Id: I83e7bfa04cde5093c10bf2bc27af5ec03da4b48e
Closes-bug: #1236326