Fixed kube-up.sh to point to the right place.

With recent changes in apiserver, URL.Path == "/" simply returns http.StatusNotFound, instead of index.html anymore. But kube-up.sh still points to "/" at the end of building a new cluster. Fixed kube-up.sh to point to the right place.

Nit: might as well remove this line, since it goes the same place as the "/" handler.