Vendor in latest k8s.io changes

These changes allow for the container's pid namespace to be set to the same
as the pod infra container's namespace if the pid namespace mode is set to POD

Signed-off-by: umohnani8 <umohnani@redhat.com>

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

@@ -21,7 +21,8 @@ import (
 	"fmt"
 	"io/ioutil"
 	"os"
-	"os/exec"
+
+	"k8s.io/kubernetes/pkg/util/nsenter"
 
 	"github.com/golang/glog"
 )
@@ -54,25 +55,20 @@ type NsenterWriter struct{}
 // 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 {
-	cmd := "nsenter"
-	baseArgs := []string{
-		"--mount=/rootfs/proc/1/ns/mnt",
-		"--",
-	}
-
-	echoArgs := append(baseArgs, "sh", "-c", fmt.Sprintf("cat > %s", filename))
-	glog.V(5).Infof("Command to write data to file: %v %v", cmd, echoArgs)
-	command := exec.Command(cmd, echoArgs...)
-	command.Stdin = bytes.NewBuffer(data)
+	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.SetStdin(bytes.NewBuffer(data))
 	outputBytes, err := command.CombinedOutput()
 	if err != nil {
 		glog.Errorf("Output from writing to %q: %v", filename, string(outputBytes))
 		return err
 	}
 
-	chmodArgs := append(baseArgs, "chmod", fmt.Sprintf("%o", perm), filename)
-	glog.V(5).Infof("Command to change permissions to file: %v %v", cmd, chmodArgs)
-	outputBytes, err = exec.Command(cmd, chmodArgs...).CombinedOutput()
+	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()
 	if err != nil {
 		glog.Errorf("Output from chmod command: %v", string(outputBytes))
 		return err