hack/quickstart/init-master.sh: Fix bootkube command.
hack/quickstart/init-master.sh: Fix bootkube command.

A simple fix because the bootkube is not running in rkt container now.

diegs/bootkube,dghubble/bootkube,dghubble/bootkube,dghubble/bootkube,ericchiang/bootkube,ericchiang/bootkube,hongchaodeng/bootkube,hongchaodeng/bootkube,ericchiang/bootkube,kubernetes-incubator/bootkube,kubernetes-incubator/bootkube,diegs/bootkube,hongchaodeng/bootkube,kubernetes-incubator/bootkube,diegs/bootkube