Mark kubelet's master-service-namespace flag deprecated

This flag is already deprecated in the API server:
- https://kubernetes.io/docs/admin/kube-apiserver/
- https://kubernetes.io/docs/admin/federation-apiserver/

cmd/kubelet/app/options/options.go

@@ -218,6 +218,7 @@ func (c *kubeletConfiguration) addFlags(fs *pflag.FlagSet) {
 	fs.BoolVar(&c.RegisterNode, "register-node", c.RegisterNode, "Register the node with the apiserver (defaults to true if --api-servers is set)")
 	fs.StringVar(&c.ClusterDomain, "cluster-domain", c.ClusterDomain, "Domain for this cluster.  If set, kubelet will configure all containers to search this domain in addition to the host's search domains")
 	fs.StringVar(&c.MasterServiceNamespace, "master-service-namespace", c.MasterServiceNamespace, "The namespace from which the kubernetes master services should be injected into pods")
+	fs.MarkDeprecated("master-service-namespace", "This flag will be removed in a future version.")
 	fs.StringSliceVar(&c.ClusterDNS, "cluster-dns", c.ClusterDNS, "Comma-separated list of DNS server IP address.  This value is used for containers DNS server in case of Pods with \"dnsPolicy=ClusterFirst\". Note: all DNS servers appearing in the list MUST serve the same set of records otherwise name resolution within the cluster may not work correctly. There is no guarantee as to which DNS server may be contacted for name resolution.")
 	fs.DurationVar(&c.StreamingConnectionIdleTimeout.Duration, "streaming-connection-idle-timeout", c.StreamingConnectionIdleTimeout.Duration, "Maximum time a streaming connection can be idle before the connection is automatically closed. 0 indicates no timeout. Example: '5m'")
 	fs.DurationVar(&c.NodeStatusUpdateFrequency.Duration, "node-status-update-frequency", c.NodeStatusUpdateFrequency.Duration, "Specifies how often kubelet posts node status to master. Note: be cautious when changing the constant, it must work with nodeMonitorGracePeriod in nodecontroller.")

pkg/kubemark/hollow_kubelet.go

@@ -19,7 +19,6 @@ package kubemark
 import (
 	"time"
 
-	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
 	kubeletapp "k8s.io/kubernetes/cmd/kubelet/app"
 	"k8s.io/kubernetes/cmd/kubelet/app/options"
 	"k8s.io/kubernetes/pkg/api"
@@ -125,7 +124,6 @@ func GetHollowKubeletConfig(
 	c.Address = "0.0.0.0" /* bind address */
 	c.Port = int32(kubeletPort)
 	c.ReadOnlyPort = int32(kubeletReadOnlyPort)
-	c.MasterServiceNamespace = metav1.NamespaceDefault
 	c.PodManifestPath = manifestFilePath
 	c.FileCheckFrequency.Duration = 20 * time.Second
 	c.HTTPCheckFrequency.Duration = 20 * time.Second