clientv3: fix client balancer with gRPC v1.7

Signed-off-by: Gyu-Ho Lee <gyuhox@gmail.com>

clientv3/example_test.go

@@ -16,12 +16,14 @@ package clientv3_test
 
 import (
 	"log"
+	"os"
 	"time"
 
 	"github.com/coreos/etcd/clientv3"
 	"github.com/coreos/etcd/pkg/transport"
-	"github.com/coreos/pkg/capnslog"
+
 	"golang.org/x/net/context"
+	"google.golang.org/grpc/grpclog"
 )
 
 var (
@@ -31,8 +33,7 @@ var (
 )
 
 func Example() {
-	var plog = capnslog.NewPackageLogger("github.com/coreos/etcd", "clientv3")
-	clientv3.SetLogger(plog)
+	clientv3.SetLogger(grpclog.NewLoggerV2(os.Stderr, os.Stderr, os.Stderr))
 
 	cli, err := clientv3.New(clientv3.Config{
 		Endpoints:   endpoints,