Updated openstack/openstack
Project: openstack/oslo.db  58cfd8262e3a071b042fadedccfa229633fb3702

Assert exceptions based on API, not string messages

The tests/sqlalchemy/test_exc_filters.py tests were asserting
the exact string format of SQLAlchemy exceptions.
SQLAlchemy is improving its exception format in version 1.0,
thereby breaking these tests.  Instead of supporting multiple
string formats, change the assertions to compare specific
fields per the oslo.db.exceptions and sqlalchemy.exc APIs.

Change-Id: Ie98ac3ca82a1052c463ca9ca5d41e228935497b3