Introduce HYPERKUBE_IMAGE_REPO variable which is set to CoreOS
hyperkube by default. Also remove "_coreos.0" from script as it can be a
different build number. This number should be included in the kubernetes
version parameters and not in scripts.
With this, it is possible to use any combination of hyperkube image with
any tags. by default we use the CoreOS one.
Partially-Implements: blueprint support-insecure-registry
Partially-Implements: blueprint coreos-best-pratice
Change-Id: Ie0fbed4b160fa972cfe130c252e87765690e2f5f
8b3ebbe8bf