misc: fix integrationtest cinder volume workaround

The workaround for cinder-volume services initally implemented with commit 0caefb1d75648bd79431e026bed102850b1a3ca8, broke with the introduction of the readinessProbe inside the cinder-volume sts inside 52c173083b24cdd6200526890d4af3b3433b9853, because the integration tests would already fail while waiting for the pods to become ready before the cinder-volume sts could be restarted. Fixed by restarting the sts during the readiness check if Openstack reports that a volume service is disabled.