Automatic merge from submit-queue

[e2e] kubectl stdin

Problem:  Currently kubectl heavily relies on files which have to be (for lack of a better word :):):)) "written" to the file system.  This hinders adoption of something like gobindata, by forcing an intermediary generated-assets directory type thing.

Solution: Lets migrate `kubectl.go` testing over to using standard input streams.

cc @kubernetes/sig-testing @timothysc