test_api_server was not waiting for rollout to finish and that was causing issues in follow up tests randomly. This patch adds an option to wait for rollout to finish when setting service config. It can be used in other tests wherever needed. Resolves: https://issues.redhat.com/browse/OSPRH-14166 Change-Id: Iabafe97934ed2b5ed40f1c529d6f2ffddeac2797