vol-salvage: VOL_DONE deleted volumes

vol-salvage: VOL_DONE deleted volumes

When the salvager deletes a volume (because it is an invalid RO clone,
or because there is no data associated with the volume), we should
inform the fileserver that the volume is gone. Otherwise, the volume
in the fileserver can get put into an error state (in DAFS) when it
tries to attach the volume, preventing anything from creating or using
that volume.

Reviewed-on: http://gerrit.openafs.org/4118
Tested-by: BuildBot <buildbot@rampaginggeek.com>
Reviewed-by: Derrick Brashear <shadow@dementia.org>
(cherry picked from commit a862d2df93fd4e8c8c7a0b8eebe9e59b75f54072)

Change-Id: I4ec62d4c6b06678af6e8e499e9dafb2d0698c9ab
Reviewed-on: http://gerrit.openafs.org/4167
Tested-by: BuildBot <buildbot@rampaginggeek.com>
Reviewed-by: Derrick Brashear <shadow@dementia.org>