butc: do not use stack garbage for secobj

The butc only ever handles connections over rxnull anyway, so just
specify an array of security objects of length one.

Reviewed-on: http://gerrit.openafs.org/9140
Tested-by: BuildBot <buildbot@rampaginggeek.com>
Reviewed-by: Simon Wilkinson <simonxwilkinson@gmail.com>
Reviewed-by: Derrick Brashear <shadow@your-file-system.com>
(cherry picked from commit 252a5b65c30636bf5f62a49a79e5777004ecd17d)

Change-Id: I0b5c112f56553b7ee0ea4e40a9c65f2fe45f8297
Reviewed-on: http://gerrit.openafs.org/9404
Reviewed-by: Jeffrey Altman <jaltman@your-file-system.com>
Tested-by: BuildBot <buildbot@rampaginggeek.com>
Reviewed-by: Derrick Brashear <shadow@your-file-system.com>
Reviewed-by: Andrew Deason <adeason@sinenomine.net>
Reviewed-by: Paul Smeddle <paul.smeddle@gmail.com>
Reviewed-by: Stephan Wiesand <stephan.wiesand@desy.de>