Updated openstack/openstack
Project: openstack/oslo.db  29e229a0539b730f30e2962930cb73008224451c

Make test_models pass on py3

Add a check that models.ModelBase is iterable.
Remove checking on next() method since models.modelBase
isn't actually iterator.
Remove unnecessary checks from TimestampMixinTest

Change-Id: Ibbde0e49bec25e1acddaf64f03083cf46481a581