Use oslo_db.sqlalchemy.test_fixtures
Use oslo_db.sqlalchemy.test_fixtures

The change in Iaf77db73e368aee0d09b4c8e76f180f394f1aa37
makes use of oslo_db.tests.*, which was not the intent of the
deprecations added to oslo_db in
I0163e637ffef6d45d2573ebe29b5438911d01fce.   Make use of the
newer fixtures in oslo_db.sqlalchemy.test_fixtures which is
what was intended to supersede oslo_db.sqlalchemy.test_base.

Change-Id: I49a5e61345ce7c90a527367ae69a28ac04295865
(cherry picked from commit 2bc0f147058d6e0d3ca523f42a70c747b587ebaf)

Datera/cinder,Datera/cinder