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>.
e2e: don't require heapster
As heapster is now deprecated, we shouldn't require it for e2e tests to pass.
```release-note
NONE
```