Finalizer issue w/ mt ping source deployment

[matzew]

Running the mt ping source on openshift, I get:

{"level":"info","ts":"2020-04-28T11:29:50.023Z","logger":"controller.event-broadcaster","caller":"record/event.go:274","msg":"Event(v1.ObjectReference{Kind:\"PingSource\", Namespace:\"test-ping-source-v1-alpha2-frrdr\", Name:\"e2e-ping-source\", UID:\"292342d2-a30c-46cd-9277-15e8642a1282\", APIVersion:\"sources.knative.dev/v1alpha1\", ResourceVersion:\"195756\", FieldPath:\"\"}): type: 'Warning' reason: 'PingSourceDeploymentCreated' Cluster-scoped deployment not created (deployments.apps \"pingsource-mt-adapter\" is forbidden: cannot set blockOwnerDeletion if an ownerReference refers to a resource you can't set finalizers on: , <nil>)","commit":"69f5d21"}

Looks like related to #3040