Fix url index out of range error in service

* if there is no node port, service panics accessing url
* since the length of array is 3 when there is no node port, accessing u[3] results in
	index out of range

Author: anoop142

cmd/minikube/cmd/service.go

@@ -260,6 +260,12 @@ func mutateURLs(serviceName string, urls []string) ([]string, error) {
 
 func openURLs(urls [][]string) {
 	for _, u := range urls {
+
+		if len(u) < 4{
+			klog.Warning("No URL found")
+			continue
+		}
+
 		_, err := url.Parse(u[3])
 		if err != nil {
 			klog.Warningf("failed to parse url %q: %v (will not open)", u[3], err)