volser: -log restore operations

Add vos restore to the list of operations which are logged
when the volserver is running with the -log option. Example
log line:

    admin on 172.16.50.141 is executing Restore 536870969

Reviewed-on: http://gerrit.openafs.org/9926
Tested-by: BuildBot <buildbot@rampaginggeek.com>
Reviewed-by: Mark Vitale <mvitale@sinenomine.net>
Reviewed-by: Derrick Brashear <shadow@your-file-system.com>
(cherry picked from commit eb7b3dac482ed0427b6e618bf60507a7a1a99769)

Change-Id: If09d8d170c14cfd71c181cbdc87c6027ee570c45
Reviewed-on: http://gerrit.openafs.org/11153
Reviewed-by: Chas Williams - CONTRACTOR <chas@cmf.nrl.navy.mil>
Reviewed-by: Perry Ruiter <pruiter@sinenomine.net>
Reviewed-by: Benjamin Kaduk <kaduk@mit.edu>
Tested-by: BuildBot <buildbot@rampaginggeek.com>
Reviewed-by: Andrew Deason <adeason@sinenomine.net>
Reviewed-by: Stephan Wiesand <stephan.wiesand@desy.de>