- make kube::util::find-binary return an error when it doesn't find
      anything so that hack scripts fail fast instead of with "binary not
      found errors".
    - this required deleting some genfeddoc stuff. the binary no longer
      exists in k/k repo since we removed federation/, and I don't see it
      in https://github.com/kubernetes-sigs/kubefed/ either. I'm assuming
      that it's gone for good now.