Track the sources that the kubelet has seen, and only delete pods
when every source has been seen at least once.
Add kubernetes-test.tar.gz

Add test artifacts to the build. This lets you do:

tar -xzf kubernetes.tar.gz
tar -xzf kubernetes-test.tar.gz
cd kubernetes
go run ./hack/e2e.go -up -test -down

without having a git checkout.
Merge pull request #3007 from zmerlynn/testtar

Add kubernetes-test.tar.gz
Merge pull request #2994 from brendandburns/exec

Track the sources that the kubelet has seen