viced: VNOVOL on deleted volumes

viced: VNOVOL on deleted volumes

When the volserver deletes a volume, the fileserver should respond to
future access to that volume with VNOVOL and not VOFFLINE, since the
volume doesn't exist anymore. Do this in DAFS via a new state,
VOL_STATE_DELETED, and in non-DAFS by just setting specialStatus to
VNOVOL.

In the future we should also make sure the vp's for deleted volumes
get freed after a couple of hours, but not yet.

Change-Id: I6dec3e0a5e9e54f6ad09fad9f2355b513cce3bf6
Reviewed-on: http://gerrit.openafs.org/2533
Tested-by: Andrew Deason <adeason@sinenomine.net>
Reviewed-by: Jeffrey Altman <jaltman@openafs.org>
Reviewed-by: Derrick Brashear <shadow@dementia.org>
Tested-by: Derrick Brashear <shadow@dementia.org>