Convert Nova to use Oslo service infrastructure.

Convert Nova to use the Oslo versions of:
* Service
* Launchers

Also add Service timers to the Service ThreadGroup.

blueprint use-oslo-services

Change-Id: Id8ab017f4525afd69fed322311f2d5cc3b6d6f98
Merge "Convert Nova to use Oslo service infrastructure."
Merge remote-tracking branch 'm_src_repo/citrix-fixes' into build-temp