afs: remove cruft from Solaris afs_freevfs

Remove some unused variables left behind in a previous
refactor of flushing vcaches during afs_shutdown
(commit 80fe111f0044aa7a67215ad92210dc72cb7eb2c0).

Change-Id: Ie0a23cb08fc2946f1c400b8ce8e15ef3dc22ec20
Reviewed-on: http://gerrit.openafs.org/11310
Tested-by: BuildBot <buildbot@rampaginggeek.com>
Reviewed-by: Chas Williams - CONTRACTOR <chas@cmf.nrl.navy.mil>
Reviewed-by: D Brashear <shadow@your-file-system.com>