Don't add http:// prefix for kubernetes services

The host:port will become a http url if necessary in doPost in proxy.go.
However, adding the http:// here prevents GRPC from working.

Fixes stripe#762

kubernetes.go

@@ -83,8 +83,7 @@ func (kd *KubernetesDiscoverer) GetDestinationsForService(serviceName string) ([
 			continue
 		}
 
-		// prepend with // so that it is a valid URL parseable by url.Parse
-		podIp := fmt.Sprintf("http://%s:%s", pod.Status.PodIP, forwardPort)
+		podIp := fmt.Sprintf("%s:%s", pod.Status.PodIP, forwardPort)
 		ips = append(ips, podIp)
 	}
 	return ips, nil