Correct a misuse of RestController in the Event API

When nested RestControllers exist, in order to determine which
arguments are associated with the parent resource, pecan looks at the
get_one() method signature in the parent controller.

TraitsController needs the EventTypesController.get_one method to exist in
order to properly pass the `event_type` identifier.

Change-Id: Ic1704c8f9c810ada4e22e8de75ef2511006e8d9d
Update oslo

This updates to:

commit b3e5166e3f47148856d898c4653b0c089c2315f5
Merge: 0002ffa 39e1c5c
Author: Jenkins <jenkins@review.openstack.org>
Date:   Thu Jan 30 10:18:54 2014 +0000

    Merge "Move db tests base.py to common code"

Change-Id: Iaa76b1165e195f0c3874bc5c8bcbc9ecbb6ca5d7
Merge "Correct a misuse of RestController in the Event API"