Make libvirt-coreos generate a .kubeconfig file and have e2e tests use it

cluster/libvirt-coreos/util.sh

@@ -220,6 +220,13 @@ function kube-up {
     rm $domain_xml
   done
 
+  export KUBECONFIG="${HOME}/.kube/.kubeconfig"
+  local kubectl="${KUBE_ROOT}/cluster/kubectl.sh"
+
+  "${kubectl}" config set-cluster libvirt-coreos --server=http://${KUBE_MASTER_IP-}:8080
+  "${kubectl}" config set-context libvirt-coreos --cluster=libvirt-coreos
+  "${kubectl}" config use-context libvirt-coreos --cluster=libvirt-coreos
+
   wait-cluster-readiness
 
   echo "Kubernetes cluster is running. The master is running at:"