Merge pull request kubernetes#76859 from SataQiu/fix-kubeadm-20190420

kubeadm: use 'errors.Errorf' instead of 'fmt.Errorf'

Author: k8s-ci-robot

cmd/kubeadm/app/discovery/token/BUILD

@@ -45,5 +45,8 @@ go_test(
     name = "go_default_test",
     srcs = ["token_test.go"],
     embed = [":go_default_library"],
-    deps = ["//staging/src/k8s.io/client-go/tools/clientcmd/api:go_default_library"],
+    deps = [
+        "//staging/src/k8s.io/client-go/tools/clientcmd/api:go_default_library",
+        "//vendor/github.com/pkg/errors:go_default_library",
+    ],
 )

cmd/kubeadm/app/discovery/token/token_test.go

@@ -17,10 +17,11 @@ limitations under the License.
 package token
 
 import (
-	"fmt"
 	"testing"
 	"time"
 
+	"github.com/pkg/errors"
+
 	clientcmdapi "k8s.io/client-go/tools/clientcmd/api"
 )
 
@@ -71,7 +72,7 @@ func TestFetchKubeConfigWithTimeout(t *testing.T) {
 		t.Run(test.name, func(t *testing.T) {
 			cfg, err := fetchKubeConfigWithTimeout(testAPIEndpoint, test.discoveryTimeout, func(apiEndpoint string) (*clientcmdapi.Config, error) {
 				if apiEndpoint != testAPIEndpoint {
-					return nil, fmt.Errorf("unexpected API server endpoint:\n\texpected: %q\n\tgot: %q", testAPIEndpoint, apiEndpoint)
+					return nil, errors.Errorf("unexpected API server endpoint:\n\texpected: %q\n\tgot: %q", testAPIEndpoint, apiEndpoint)
 				}
 
 				time.Sleep(3 * time.Second)