[placement]os_region_name has been deprecated in favor of
[placement]region_name [1], and other usages removed [2].
[placement]os_interfaces has been deprecated in favor of
[placement]valid_interfaces.
This change removes the deprecated options, for the requisite time hath
elapsed.
[1] https://review.openstack.org/#/c/492247/
[2] Iea7d5d0d6907adbcb236dc43b5af7469de2ba78b
Change-Id: Ide57fecf92a22c13884b872b3007e77a059e8b08