pmem-csi-driver: idempotent removal of target dir in NodeUnpublishVolume

If the target directory already was removed earlier, os.Remove returns
ErrNotExist, which must be ignored.

Found accidentally on Clear Linux during the "can mount again after
restart" test: there (and not on Fedora!) the target directory created
by the driver didn't survive the sudden power loss, and then
NodeUnpublishVolume failed.

pkg/pmem-csi-driver/nodeserver.go

@@ -418,9 +418,11 @@ func (ns *nodeServer) NodeUnpublishVolume(ctx context.Context, req *csi.NodeUnpu
 		}
 	}
 
-	if err := os.Remove(targetPath); err != nil {
+	err = os.Remove(targetPath)
+	if err != nil && !errors.Is(err, os.ErrNotExist) {
 		return nil, status.Error(codes.Internal, "unexpected error while removing target path: "+err.Error())
 	}
+	klog.V(5).Infof("NodeUnpublishVolume: volume id:%s targetpath:%s has been removed with error: %v", req.VolumeId, targetPath, err)
 
 	if p.GetPersistency() == parameters.PersistencyEphemeral {
 		if _, err := ns.cs.DeleteVolume(ctx, &csi.DeleteVolumeRequest{VolumeId: vol.ID}); err != nil {