Comment 4 for bug 1734504

We probably can't get the old/new flavor information off the instance either, because the migration.instance_uuid record points at an instance but the old/new flavor in that instance might no longer match that specific migration record, e.g. if I have resized an instance twice, from flavor A->B and then flavor B->C, there would be 2 migration records pointing at the same instance but the first migration can't get the old/new flavors off the instance because the current old/new flavors on the instance record are B/C, not A/B.

The only way I see that we can really fix this is to change the migrations.old/new_instance_type columns in the database so we can store the flavorid (string) rather than the flavor.id (int).