vol: fix everything to use volumeid type

use one type for volumeid, not 3. kill VolId, and stop
using afs_uint32 (and a few times, afs_int32)

Change-Id: Ibcbd09b5a24d8720b02a02f926e6f59dc0f529aa
Reviewed-on: http://gerrit.openafs.org/8845
Tested-by: BuildBot <buildbot@rampaginggeek.com>
Reviewed-by: Chas Williams - CONTRACTOR <chas@cmf.nrl.navy.mil>
Reviewed-by: Derrick Brashear <shadow@your-file-system.com>