Any error result from PreBind was treated as a pod scheduling failure. This was
overlooked when moving blocking API calls in the DRA plugin into a PreBind
implementation, leading to:
E0604 15:45:50.980929 306340 schedule_one.go:1048] "Error scheduling pod; retrying" err="waiting for resource driver" pod="test/test-draqld28"
That's because DRA's PreBind does some updates in the apiserver, then returns
Pending to wait for the outcome.
The fix is to allow PreBind to return the same special status codes as other
extension points.
c339eafb76