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.
There are some functions of e2e test framework and it is useful to
read the test code by using these functions.
This replaces gomega calls with these functions under test/e2e/node/
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
