ubik: remove unused ContactQuorum_DISK_Write

ubik: remove unused ContactQuorum_DISK_Write

This function is not used; remove it.

No functional change is incurred by this commit.

Reviewed-on: https://gerrit.openafs.org/13077
Reviewed-by: Andrew Deason <adeason@sinenomine.net>
Reviewed-by: Michael Meffie <mmeffie@sinenomine.net>
Reviewed-by: Marcio Brito Barbosa <mbarbosa@sinenomine.net>
Tested-by: BuildBot <buildbot@rampaginggeek.com>
Reviewed-by: Benjamin Kaduk <kaduk@mit.edu>
(cherry picked from commit 8b1e730c11a6ed7dc067ef185302bd57a69f6d1e)

Change-Id: I548e2442684a26ab017afebb1c42bdef9bd7c7bf
Reviewed-on: https://gerrit.openafs.org/13187
Reviewed-by: Michael Meffie <mmeffie@sinenomine.net>
Reviewed-by: Andrew Deason <adeason@sinenomine.net>
Reviewed-by: Joe Gorse <jhgorse@gmail.com>
Reviewed-by: Mark Vitale <mvitale@sinenomine.net>
Reviewed-by: Marcio Brito Barbosa <mbarbosa@sinenomine.net>
Reviewed-by: Cheyenne Wills <cwills@sinenomine.net>
Tested-by: BuildBot <buildbot@rampaginggeek.com>
Reviewed-by: Stephan Wiesand <stephan.wiesand@desy.de>