vos: restore status information to 'vos status'

vos: restore status information to 'vos status'

Commit d3eaa39da3693bba708fa2fa951568009e929550 'rx: Make the rx_call
structure private' created accessors for several rx_call members.
However, it simply #ifdef'd out the packet counters and timestamps
reported by 'vos status' (AFSVol_Monitor).  This is a regression for the
1.8.x 'vos status' command.

Instead, supply an accessor so 'vos status' can again be used to monitor
the progress of certain volume operations.

FIXES 134856

Change-Id: I91f5831b21f128bd8e86db63387a454c9e57bcdf
Reviewed-on: https://gerrit.openafs.org/13400
Reviewed-by: Benjamin Kaduk <kaduk@mit.edu>
Tested-by: BuildBot <buildbot@rampaginggeek.com>
Reviewed-by: Mark Vitale <mvitale@sinenomine.net>