Introduce new kubelet volume manager

This commit adds a new volume manager in kubelet that synchronizes
volume mount/unmount (and attach/detach, if attach/detach controller
is not enabled).

This eliminates the race conditions between the pod creation loop
and the orphaned volumes loops. It also removes the unmount/detach
from the `syncPod()` path so volume clean up never blocks the
`syncPod` loop.

pkg/kubelet/kubelet_getters_test.go

@@ -24,7 +24,7 @@ import (
 )
 
 func TestKubeletDirs(t *testing.T) {
-	testKubelet := newTestKubelet(t)
+	testKubelet := newTestKubelet(t, false /* controllerAttachDetachEnabled */)
 	kubelet := testKubelet.kubelet
 	root := kubelet.rootDirectory
 
@@ -86,7 +86,7 @@ func TestKubeletDirs(t *testing.T) {
 }
 
 func TestKubeletDirsCompat(t *testing.T) {
-	testKubelet := newTestKubelet(t)
+	testKubelet := newTestKubelet(t, false /* controllerAttachDetachEnabled */)
 	kubelet := testKubelet.kubelet
 	root := kubelet.rootDirectory
 	if err := os.MkdirAll(root, 0750); err != nil {