Add DEVICE_OWNER_BAREMETAL_PREFIX const
Add DEVICE_OWNER_BAREMETAL_PREFIX const

Ironic has own device_owner prefix

Change-Id: Ie79f39b2e87411feeca6851a8e59d9b9984b0207
Closes-bug: 1606229 (partially)

openstack/neutron-lib,openstack/neutron-lib,openstack/neutron-lib,openstack/neutron-lib