volinfo: refactor global options

Move the global options to a structure and pass it to the vol-info
functions. This is a precursor for creating separate volinfo and
volscan programs.

Reviewed-on: http://gerrit.openafs.org/10902
Reviewed-by: D Brashear <shadow@your-file-system.com>
Tested-by: D Brashear <shadow@your-file-system.com>
(cherry picked from commit 77e4d2146e166c5c70d4255408bde5e6499a06bf)

Change-Id: Id97ba0bfecb8104288f904b5efe693a6e652d844
Reviewed-on: http://gerrit.openafs.org/11277
Tested-by: BuildBot <buildbot@rampaginggeek.com>
Reviewed-by: Andrew Deason <adeason@sinenomine.net>
Reviewed-by: Stephan Wiesand <stephan.wiesand@desy.de>