ptserver: Rename ubik.c as ptubik.c

Coverity gets confused between ubik/ubik.c and ptserver/ubik.c,
and produces a load of false positives. Rename the ptserver ubik
shim (which is only used by pt_util) in order to reduce this
confusion.

Reviewed-on: http://gerrit.openafs.org/9273
Reviewed-by: Chas Williams - CONTRACTOR <chas@cmf.nrl.navy.mil>
Tested-by: BuildBot <buildbot@rampaginggeek.com>
Reviewed-by: Jeffrey Altman <jaltman@your-file-system.com>
(cherry picked from commit daed548f70a2187c679232e4f79d703389419c4e)

Change-Id: I834fab3b65859cb73ece3fc52d9272d0b7d452ed
Reviewed-on: http://gerrit.openafs.org/11012
Reviewed-by: Chas Williams - CONTRACTOR <chas@cmf.nrl.navy.mil>
Reviewed-by: Andrew Deason <adeason@sinenomine.net>
Tested-by: BuildBot <buildbot@rampaginggeek.com>
Reviewed-by: Benjamin Kaduk <kaduk@mit.edu>
Reviewed-by: Stephan Wiesand <stephan.wiesand@desy.de>