Adding a root filesystem override for kubelet mounter

This is useful for supporting hostPath volumes via containerized
mounters in kubelet.

Signed-off-by: Vishnu kannan <vishnuk@google.com>

cmd/kube-proxy/app/conntrack.go

@@ -67,7 +67,7 @@ func (realConntracker) SetTCPEstablishedTimeout(seconds int) error {
 func isSysFSWritable() (bool, error) {
 	const permWritable = "rw"
 	const sysfsDevice = "sysfs"
-	m := mount.New("" /* default mount path */)
+	m := mount.New()
 	mountPoints, err := m.List()
 	if err != nil {
 		glog.Errorf("failed to list mount points: %v", err)