Fix FK violation in ConsoleTestCase

setUp() of ConsoleTestCase creates a few Console instances
that reference a non-existing instance with generated UUID
value. The tests work great on SQLite (because FKs are disabled),
but fail on MySQL and PostgreSQL.

Blueprint: db-api-tests-on-all-backends

Change-Id: I2417b6f6dad8c9c84af8b49a3c6db8b9bb715e56
Merge "Fix FK violation in ConsoleTestCase"