Implement ModelsMigrationsSync test from oslo.db

Add tests to verify that database migrations produce
the same schema as the database models.

Also for MySQL, check that all tables are configured to use InnoDB
as the storage engine.
These tests make use of the ModelsMigrationsSync test class from
oslo.db and the load_tests protocol from Python unittest.

Closes-bug: #1346444

Change-Id: Ic0e7eb37c30cc5e94cbdbddf07a6dc1ebf377c17
Merge "Implement ModelsMigrationsSync test from oslo.db"