Remove update_service_capabilities from nova

From the comments of update_service_capabilities, it is said that
once publish_service_capabilities was removed, then we can begin the
process of its removal.

publish_service_capabilities has been removed in patch
I31c21055163e94b712d337568b16b9b7a224b52f, so we can remove
update_service_capabilities now.

Change-Id: I46be33462321f5e3ff0904bdff8dbfe2fbe115cd
Closes-Bug: #1263569
Merge "Remove update_service_capabilities from nova"