Bz1129462 openstack handle metering

Fix a bug where the Metering Service (Ceilometer) was not appropriately wrapped in the new Openstack Service Delegate construct introduced for Tenant support in ManageIQ.

This also introduces the ability for new Openstack services to be supported without requiring a service wrapper.

https://bugzilla.redhat.com/show_bug.cgi?id=1129462
OK, but I meant is it optional in OpenStack. If it isn't, like nova, then there's no need to add it to the fallback list.