volinfo: fix file size data type

Use afs_sfsize_t for file size instead of int.

Reviewed-on: http://gerrit.openafs.org/4737
Tested-by: BuildBot <buildbot@rampaginggeek.com>
Reviewed-by: Derrick Brashear <shadow@dementia.org>
(cherry picked from commit 8eddff4b785a196b2aae8be2d3a0e75fa3b6c0cf)

Change-Id: I670949abbb9ebfd652bb8baddcef47c7bad1b211
Reviewed-on: http://gerrit.openafs.org/11255
Reviewed-by: Chas Williams - CONTRACTOR <chas@cmf.nrl.navy.mil>
Reviewed-by: Andrew Deason <adeason@sinenomine.net>
Tested-by: BuildBot <buildbot@rampaginggeek.com>
Reviewed-by: Stephan Wiesand <stephan.wiesand@desy.de>