Updated openstack/openstack
Project: openstack/oslo.db  91d554ab55d066e3d695fad4343ea2c9e483a5fa

Remove moxstubout.py from oslo.db

Remove moxstubout.py from common/fixture becouse it is
duplicated in oslotest

Change-Id: I6480c24a1b6f9d01af918d416ca14439cff31db0