Don't delete VSes not owned by the reconciling Ingress. (#6342)
Don't delete VSes not owned by the reconciling Ingress. (#6342)

* Don't use RouteLabelKey when deleting VirtualService.

* Keep old deletion logic, but ignore NotOwned resources.

* Undo the label changes, save for follow-up.

* Undo the label change, save for follow up.

knative-sandbox/net-istio,knative-sandbox/net-istio