Use the same pattern everywhere in the e2e test
harness, use busybox (from dockerhub) instead
of using the one from k8s.gcr.io registry.
Change-Id: I57c3b867408c1f9478a8909c26744ea0368ff003
Automatic merge from submit-queue. If you want to cherry-pick this change to another branch, please follow the instructions <a href="https://github.com/kubernetes/community/blob/master/contributors/devel/cherry-picks.md">here</a>.
NetworkPolicy e2e: use ClientSet and update to CoreV1 and NetworkingV1 apis.
**What this PR does / why we need it**:
Update NetworkPolicy e2e test: use the public ClientSet and update to CoreV1 and NetworkingV1 apis.
**Release note**:
```release-note
NONE
```