fix: only cleanup empty parent directories during DeleteVolume

[andyzhangx]

What type of PR is this?
/kind bug

What this PR does / why we need it:

fix: only cleanup empty parent directories during DeleteVolume

[pod/csi-nfs-controller-6dcc8cc68c-mn26w/nfs] I0313 10:33:11.629160       1 utils.go:111] GRPC call: /csi.v1.Controller/DeleteVolume
[pod/csi-nfs-controller-6dcc8cc68c-mn26w/nfs] I0313 10:33:11.629419       1 utils.go:112] GRPC request: {"secrets":"***stripped***","volume_id":"nfs-server.default.svc.cluster.local##nfs-270/pvc-dxb27#pvc-ce9651cb-815e-463c-bd67-a7215b97b85c#"}
[pod/csi-nfs-controller-6dcc8cc68c-mn26w/nfs] I0313 10:33:11.630434       1 controllerserver.go:226] DeleteVolume: found mountOptions(nfsvers=4.1) for volume(nfs-server.default.svc.cluster.local##nfs-270/pvc-dxb27#pvc-ce9651cb-815e-463c-bd67-a7215b97b85c#)
[pod/csi-nfs-controller-6dcc8cc68c-mn26w/nfs] I0313 10:33:11.630557       1 controllerserver.go:525] internally mounting nfs-server.default.svc.cluster.local:/ at /tmp/pvc-ce9651cb-815e-463c-bd67-a7215b97b85c
[pod/csi-nfs-controller-6dcc8cc68c-mn26w/nfs] I0313 10:33:11.630729       1 nodeserver.go:133] NodePublishVolume: volumeID(nfs-server.default.svc.cluster.local##nfs-270/pvc-dxb27#pvc-ce9651cb-815e-463c-bd67-a7215b97b85c#) source(nfs-server.default.svc.cluster.local:/) targetPath(/tmp/pvc-ce9651cb-815e-463c-bd67-a7215b97b85c) mountflags([nfsvers=4.1])
[pod/csi-nfs-controller-6dcc8cc68c-mn26w/nfs] I0313 10:33:11.630993       1 mount_linux.go:270] Mounting cmd (mount) with arguments (-t nfs -o nfsvers=4.1 nfs-server.default.svc.cluster.local:/ /tmp/pvc-ce9651cb-815e-463c-bd67-a7215b97b85c)
[pod/csi-nfs-controller-6dcc8cc68c-mn26w/nfs] I0313 10:33:11.675955       1 nodeserver.go:153] skip chmod on targetPath(/tmp/pvc-ce9651cb-815e-463c-bd67-a7215b97b85c) since mountPermissions is set as 0
[pod/csi-nfs-controller-6dcc8cc68c-mn26w/nfs] I0313 10:33:11.676031       1 nodeserver.go:155] volume(nfs-server.default.svc.cluster.local##nfs-270/pvc-dxb27#pvc-ce9651cb-815e-463c-bd67-a7215b97b85c#) mount nfs-server.default.svc.cluster.local:/ on /tmp/pvc-ce9651cb-815e-463c-bd67-a7215b97b85c succeeded
[pod/csi-nfs-controller-6dcc8cc68c-mn26w/nfs] I0313 10:33:11.676084       1 controllerserver.go:295] removing subdirectory at /tmp/pvc-ce9651cb-815e-463c-bd67-a7215b97b85c/nfs-270/pvc-dxb27
[pod/csi-nfs-controller-6dcc8cc68c-mn26w/nfs] I0313 10:33:11.685621       1 controllerserver.go:302] DeleteVolume: removing empty directories in /tmp/pvc-ce9651cb-815e-463c-bd67-a7215b97b85c/nfs-270
[pod/csi-nfs-controller-6dcc8cc68c-mn26w/nfs] I0313 10:33:11.687404       1 utils.go:245] Removing empty directory /tmp/pvc-ce9651cb-815e-463c-bd67-a7215b97b85c/nfs-270
[pod/csi-nfs-controller-6dcc8cc68c-mn26w/nfs] I0313 10:33:11.688227       1 controllerserver.go:540] internally unmounting /tmp/pvc-ce9651cb-815e-463c-bd67-a7215b97b85c
[pod/csi-nfs-controller-6dcc8cc68c-mn26w/nfs] I0313 10:33:11.688245       1 nodeserver.go:176] NodeUnpublishVolume: unmounting volume nfs-server.default.svc.cluster.local##nfs-270/pvc-dxb27#pvc-ce9651cb-815e-463c-bd67-a7215b97b85c# on /tmp/pvc-ce9651cb-815e-463c-bd67-a7215b97b85c
[pod/csi-nfs-controller-6dcc8cc68c-mn26w/nfs] I0313 10:33:11.688254       1 nodeserver.go:181] force unmount nfs-server.default.svc.cluster.local##nfs-270/pvc-dxb27#pvc-ce9651cb-815e-463c-bd67-a7215b97b85c# on /tmp/pvc-ce9651cb-815e-463c-bd67-a7215b97b85c
[pod/csi-nfs-controller-6dcc8cc68c-mn26w/nfs] I0313 10:33:11.689332       1 mount_helper_common.go:56] unmounting "/tmp/pvc-ce9651cb-815e-463c-bd67-a7215b97b85c" (corruptedMount: false, mounterCanSkipMountPointChecks: true)
[pod/csi-nfs-controller-6dcc8cc68c-mn26w/nfs] I0313 10:33:11.689352       1 mount_linux.go:892] Unmounting /tmp/pvc-ce9651cb-815e-463c-bd67-a7215b97b85c
[pod/csi-nfs-controller-6dcc8cc68c-mn26w/nfs] I0313 10:33:11.724365       1 mount_helper_common.go:150] Deleting path "/tmp/pvc-ce9651cb-815e-463c-bd67-a7215b97b85c"
[pod/csi-nfs-controller-6dcc8cc68c-mn26w/nfs] I0313 10:33:11.724912       1 nodeserver.go:189] NodeUnpublishVolume: unmount volume nfs-server.default.svc.cluster.local##nfs-270/pvc-dxb27#pvc-ce9651cb-815e-463c-bd67-a7215b97b85c# on /tmp/pvc-ce9651cb-815e-463c-bd67-a7215b97b85c successfully

Which issue(s) this PR fixes:

Fixes #855

Special notes for your reviewer:

Does this PR introduce a user-facing change?:

fix: only cleanup empty parent directories during DeleteVolume

[k8s-ci-robot]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: andyzhangx

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• OWNERS [andyzhangx]

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[coveralls]

Pull Request Test Coverage Report for Build 13851790872

Details

• 26 of 41 (63.41%) changed or added relevant lines in 2 files are covered.
• No unchanged relevant lines lost coverage.
• Overall coverage decreased (-0.5%) to 77.527%

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Changes Missing Coverage	Covered Lines	Changed/Added Lines	%
pkg/nfs/controllerserver.go	5	7	71.43%
pkg/nfs/utils.go	21	34	61.76%

Totals
Change from base Build 13825626462:	-0.5%
Covered Lines:	1097
Relevant Lines:	1415

---

💛 - Coveralls

[andyzhangx]

/retest