
As per the discussion in https://review.openstack.org/190302: When AVAILABLE_REGIONS is set, OPENSTACK_HOST and OPENSTACK_KEYSTONE_URL are no longer required in local_settings as per Horizon developer documentation. This patch implements this either/or configuration. Change-Id: Iee9b41c34f770f2e8d76ef0e1e1a974f286ca6a9 Closes-Bug: #1463772