An error occurs when deleting a volume with the docker command

[Kazuhisa Hara]

When deleting a volume created with the dog command or a volume created by another server, an error is recorded.

This is because that directory does not exist on the host.

Reproduction: 100%

$ dog vdi create dvp-vol1 10G
$ docker volume rm vol1

DEBU[0426] vdi exist
INFO[0426] Remove: vol1
DEBU[0426] Count %s0
DEBU[0426] Begin utils.dogVdiDelete: dvp-vol1
DEBU[0426] utils.dogVdiCreate sheep options:
DEBU[0426] Result of dogVdiDelete:
DEBU[0426] remove path: /mnt/sheepdog/vol1
ERRO[0426] Failed to remove Mount directory: remove /mnt/sheepdog/vol1: no such file or directory