fix: remove parent dir in DeleteVolume

[andyzhangx]

What type of PR is this?
/kind bug

What this PR does / why we need it:
fix: remove parent dir in DeleteVolume

Which issue(s) this PR fixes:

Fixes #763

Special notes for your reviewer:

[pod/csi-nfs-controller-67c56ff89f-j244d/nfs] I0915 05:01:30.363893       1 utils.go:110] GRPC call: /csi.v1.Controller/DeleteVolume
[pod/csi-nfs-controller-67c56ff89f-j244d/nfs] I0915 05:01:30.364289       1 utils.go:111] GRPC request: {"secrets":"***stripped***","volume_id":"nfs-server.default.svc.cluster.local##nfs-7869/pvc-m74ps#pvc-f2772f7e-a91c-4b0e-83d5-9cb0b3da9998#"}
[pod/csi-nfs-controller-67c56ff89f-j244d/nfs] I0915 05:01:30.364360       1 controllerserver.go:225] DeleteVolume: found mountOptions(nfsvers=4.1) for volume(nfs-server.default.svc.cluster.local##nfs-7869/pvc-m74ps#pvc-f2772f7e-a91c-4b0e-83d5-9cb0b3da9998#)
[pod/csi-nfs-controller-67c56ff89f-j244d/nfs] I0915 05:01:30.364550       1 controllerserver.go:502] internally mounting nfs-server.default.svc.cluster.local:/ at /tmp/pvc-f2772f7e-a91c-4b0e-83d5-9cb0b3da9998
[pod/csi-nfs-controller-67c56ff89f-j244d/nfs] I0915 05:01:30.364894       1 nodeserver.go:132] NodePublishVolume: volumeID(nfs-server.default.svc.cluster.local##nfs-7869/pvc-m74ps#pvc-f2772f7e-a91c-4b0e-83d5-9cb0b3da9998#) source(nfs-server.default.svc.cluster.local:/) targetPath(/tmp/pvc-f2772f7e-a91c-4b0e-83d5-9cb0b3da9998) mountflags([nfsvers=4.1])
[pod/csi-nfs-controller-67c56ff89f-j244d/nfs] I0915 05:01:30.364925       1 mount_linux.go:218] Mounting cmd (mount) with arguments (-t nfs -o nfsvers=4.1 nfs-server.default.svc.cluster.local:/ /tmp/pvc-f2772f7e-a91c-4b0e-83d5-9cb0b3da9998)
[pod/csi-nfs-controller-67c56ff89f-j244d/nfs] I0915 05:01:30.394775       1 nodeserver.go:149] skip chmod on targetPath(/tmp/pvc-f2772f7e-a91c-4b0e-83d5-9cb0b3da9998) since mountPermissions is set as 0
[pod/csi-nfs-controller-67c56ff89f-j244d/nfs] I0915 05:01:30.394816       1 nodeserver.go:151] volume(nfs-server.default.svc.cluster.local##nfs-7869/pvc-m74ps#pvc-f2772f7e-a91c-4b0e-83d5-9cb0b3da9998#) mount nfs-server.default.svc.cluster.local:/ on /tmp/pvc-f2772f7e-a91c-4b0e-83d5-9cb0b3da9998 succeeded
[pod/csi-nfs-controller-67c56ff89f-j244d/nfs] I0915 05:01:30.394905       1 controllerserver.go:301] removing subdirectory at /tmp/pvc-f2772f7e-a91c-4b0e-83d5-9cb0b3da9998/nfs-7869 on internalVolumePath /tmp/pvc-f2772f7e-a91c-4b0e-83d5-9cb0b3da9998/nfs-7869/pvc-m74ps
[pod/csi-nfs-controller-67c56ff89f-j244d/nfs] I0915 05:01:30.396139       1 controllerserver.go:517] internally unmounting /tmp/pvc-f2772f7e-a91c-4b0e-83d5-9cb0b3da9998
[pod/csi-nfs-controller-67c56ff89f-j244d/nfs] I0915 05:01:30.396163       1 nodeserver.go:172] NodeUnpublishVolume: unmounting volume nfs-server.default.svc.cluster.local##nfs-7869/pvc-m74ps#pvc-f2772f7e-a91c-4b0e-83d5-9cb0b3da9998# on /tmp/pvc-f2772f7e-a91c-4b0e-83d5-9cb0b3da9998
[pod/csi-nfs-controller-67c56ff89f-j244d/nfs] I0915 05:01:30.396361       1 nodeserver.go:177] force unmount nfs-server.default.svc.cluster.local##nfs-7869/pvc-m74ps#pvc-f2772f7e-a91c-4b0e-83d5-9cb0b3da9998# on /tmp/pvc-f2772f7e-a91c-4b0e-83d5-9cb0b3da9998
[pod/csi-nfs-controller-67c56ff89f-j244d/nfs] I0915 05:01:30.396408       1 mount_helper_common.go:56] unmounting "/tmp/pvc-f2772f7e-a91c-4b0e-83d5-9cb0b3da9998" (corruptedMount: false, mounterCanSkipMountPointChecks: true)
[pod/csi-nfs-controller-67c56ff89f-j244d/nfs] I0915 05:01:30.396422       1 mount_linux.go:789] Unmounting /tmp/pvc-f2772f7e-a91c-4b0e-83d5-9cb0b3da9998
[pod/csi-nfs-controller-67c56ff89f-j244d/nfs] I0915 05:01:30.422736       1 mount_helper_common.go:150] Deleting path "/tmp/pvc-f2772f7e-a91c-4b0e-83d5-9cb0b3da9998"
[pod/csi-nfs-controller-67c56ff89f-j244d/nfs] I0915 05:01:30.423299       1 nodeserver.go:185] NodeUnpublishVolume: unmount volume nfs-server.default.svc.cluster.local##nfs-7869/pvc-m74ps#pvc-f2772f7e-a91c-4b0e-83d5-9cb0b3da9998# on /tmp/pvc-f2772f7e-a91c-4b0e-83d5-9cb0b3da9998 successfully

Does this PR introduce a user-facing change?:

fix: remove parent dir in 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 10868018354

Details

• 10 of 12 (83.33%) changed or added relevant lines in 2 files are covered.
• No unchanged relevant lines lost coverage.
• Overall coverage decreased (-0.003%) to 78.117%

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Changes Missing Coverage	Covered Lines	Changed/Added Lines	%
pkg/nfs/controllerserver.go	6	8	75.0%

Totals
Change from base Build 10866816642:	-0.003%
Covered Lines:	921
Relevant Lines:	1179

---

💛 - Coveralls