Default enable run_validation

It was default enabled on the gate for a long time.
The option is  required to run api tests stability in case the
guest cooperation required for example volume/interface detach.

https://etherpad.openstack.org/p/handling-of-interface-attach-detach-hotplug-unplug

Related-Prod: PRODX-10450

Change-Id: I9fd433fe249cc80f6799ff240df692a5ce9275a5
2 files changed