Automatic merge from submit-queue

Deleting federation-push.sh

This has bit me a few times. And based on my discussions with @madhusudancs has bit him as well.

Running federation-push.sh doesnt work anymore.
Running build/push-federation-images.sh does the right thing.
They were both trying to do the same thing anyway.

Our documentation (https://github.com/kubernetes/kubernetes/blob/master/docs/devel/e2e-tests.md#federation-e2e-tests) suggests running push-federation-images.sh.

Deleting federation-push.sh

@kubernetes/sig-cluster-federation @colhom @mml