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
The following tests are not tagged because they are not really run in
node e2e suites:
* A subset of host path tests that required SSH access
- should evaluate whether the tests should be moved to test/e2e_node
* GCP volume tests
- should evaluate whether these tests should be moved out of the
common directly since they are not shared with the node e2e suite.