Make sure owner column doesn't get dropped during downgrade

Fixes bug 1204941

The owner column was missing from the table schema. Because of limitations
of sqlite and implementation details in SQLAlchemy-migrate, this would end
up dropping the owner column during a downgrade when using sqlite.

Change-Id: If8f7f16c9b6fb059f0fcfdf8967afd37f19864b6
Merge "Make sure owner column doesn't get dropped during downgrade"