Add an action log to FakeMounter.

# *** ERROR: *** docs are out of sync between cli and markdown
# run hack/run-gendocs.sh > docs/kubectl.md to regenerate

#
# Your commit will be aborted unless you regenerate docs.
    COMMIT_BLOCKED_ON_GENDOCS

pkg/util/mount/mount_linux_test.go

@@ -94,7 +94,7 @@ func slicesEqual(a, b []string) bool {
 
 func TestGetMountRefs(t *testing.T) {
 	fm := &FakeMounter{
-		[]MountPoint{
+		MountPoints: []MountPoint{
 			{Device: "/dev/sdb", Path: "/var/lib/kubelet/plugins/kubernetes.io/gce-pd/mounts/gce-pd"},
 			{Device: "/dev/sdb", Path: "/var/lib/kubelet/pods/some-pod/volumes/kubernetes.io~gce-pd/gce-pd-in-pod"},
 			{Device: "/dev/sdc", Path: "/var/lib/kubelet/plugins/kubernetes.io/gce-pd/mounts/gce-pd2"},