Upgraded from 99c19923, branch release-3.0.
This required fetching or upgrading the following:
* k8s.io/api to kubernetes-1.9.1
* k8s.io/apimachinery to kubernetes-1.9.1
* github.com/juju/ratelimit to 1.0.1
* github.com/spf13/pflag to 4c012f6d
Also, update Scope's imports/function calls to be compatible with the new client.
This caused a dependency chain reaction (sigh):
* All the k8s packages had to be fetched again. This in turn required:
* Pining github.com/docker/docker/pkg/parsers to
0f5c9d301b9b1cca66b3ea0f9dec3b5317d3686d to cirvumvent
https://github.com/kubernetes/kubernetes/issues/18774
* Update github.com/juju/ratelimit
* Make probe/kubernetes/client.go comply with API changes.