Comment 1 for bug 1629446

Looks like this is blowing up here - https://github.com/openstack/keystone/blob/cd23e776b7631d2f7b9465ef29789fd354f7d66a/keystone/federation/utils.py#L615-L616

One way we could possibly fix this is by adding some validation to the _transform() method, making sure the identity_values['groups'] is actually a list.