vol: Avoid FDH_SEEK/FDH_READ
All code in the tree except for this uses positional i/o
(FDH_PREAD/FDH_PWRITE). For consistency and to ensure that we do not
mix positional and non-positional i/o, just use the positional i/o
functions here. It's simpler, too.
Change-Id: Ib65f81dde7532631cd7d642c9ef814d47c71581a
Reviewed-on: http://gerrit.openafs.org/11377
Tested-by: BuildBot <buildbot@rampaginggeek.com>
Reviewed-by: Hans-Werner Paulsen <hans@mpa-garching.mpg.de>
Tested-by: Hans-Werner Paulsen <hans@mpa-garching.mpg.de>
Reviewed-by: Perry Ruiter <pruiter@sinenomine.net>
Reviewed-by: Benjamin Kaduk <kaduk@mit.edu>