Update go dependencies

vendor/k8s.io/kubernetes/pkg/util/io/writer.go

@@ -50,15 +50,24 @@ func (writer *StdWriter) WriteFile(filename string, data []byte, perm os.FileMod
 // it will not see the mounted device in its own namespace. To work around this
 // limitation one has to first enter hosts namespace (by using 'nsenter') and
 // only then write data.
-type NsenterWriter struct{}
+type NsenterWriter struct {
+	ne *nsenter.Nsenter
+}
+
+// NewNsenterWriter creates a new Writer that allows writing data to file using
+// nsenter command.
+func NewNsenterWriter(ne *nsenter.Nsenter) *NsenterWriter {
+	return &NsenterWriter{
+		ne: ne,
+	}
+}
 
 // WriteFile calls 'nsenter cat - > <the file>' and 'nsenter chmod' to create a
 // file on the host.
 func (writer *NsenterWriter) WriteFile(filename string, data []byte, perm os.FileMode) error {
-	ne := nsenter.NewNsenter()
 	echoArgs := []string{"-c", fmt.Sprintf("cat > %s", filename)}
 	glog.V(5).Infof("nsenter: write data to file %s by nsenter", filename)
-	command := ne.Exec("sh", echoArgs)
+	command := writer.ne.Exec("sh", echoArgs)
 	command.SetStdin(bytes.NewBuffer(data))
 	outputBytes, err := command.CombinedOutput()
 	if err != nil {
@@ -68,7 +77,7 @@ func (writer *NsenterWriter) WriteFile(filename string, data []byte, perm os.Fil
 
 	chmodArgs := []string{fmt.Sprintf("%o", perm), filename}
 	glog.V(5).Infof("nsenter: change permissions of file %s to %s", filename, chmodArgs[0])
-	outputBytes, err = ne.Exec("chmod", chmodArgs).CombinedOutput()
+	outputBytes, err = writer.ne.Exec("chmod", chmodArgs).CombinedOutput()
 	if err != nil {
 		glog.Errorf("Output from chmod command: %v", string(outputBytes))
 		return err