"oc patch pod" fails with "Forbidden: pod updates may not change fields..."

Issue

• When trying to apply a patch to a Pod, it fails as some other field (DNSConfig in the example below) is also changed:

  $ oc patch pod -n ibm-common-services setup-job-9cv74 -p '{"metadata":{"finalizers":null}}'
  The Pod "setup-job-9cv74" is invalid: spec: Forbidden: pod updates may not change fields other than `spec.containers[*].image`, `spec.initContainers[*].image`, `spec.activeDeadlineSeconds`, `spec.tolerations` (only additions to existing tolerations) or `spec.terminationGracePeriodSeconds` (allow it to be set to 1 if it was previously negative)
    core.PodSpec{
      ... // 22 identical fields
      Priority:         &0,
      PreemptionPolicy: &"PreemptLowerPriority",
  -   DNSConfig:        &core.PodDNSConfig{Options: []core.PodDNSConfigOption{{Name: "single-request-reopen"}}},
  +   DNSConfig:        nil,
      ReadinessGates:   nil,
      RuntimeClassName: nil,
      ... // 4 identical fields
    }