Fix the `staticcheck` failures for `test/e2e/node`. All of the
staticcheck errors were for variables which were never used. When these
values were `err`, we added processing for the errors. When they were
values that were just never used, we stopped giving them a name.
This is part of the transition to using framework/log instead
of the Logf inside the framework package. This will help with
import size/cycles when importing the framework or subpackages.
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
