OpenBSD: No ruid/rgid in cred structure.

OpenBSD: No ruid/rgid in cred structure.

OpenBSD does not retain ruid or rgid values in the
afs_creds_t structure (ucred). This patch, therefore,
removes any references to them in the afs.h file. Since
no attempt is made to actually use the removed code (or
macros) on OpenBSD, at least at this time, this does
not result in any real functional change.

Reviewed-on: http://gerrit.openafs.org/3687
Tested-by: BuildBot <buildbot@rampaginggeek.com>
Reviewed-by: Derrick Brashear <shadow@dementia.org>
(cherry picked from commit a5441776b639cd32c2271917dd55fa491f9e512f)

Change-Id: I1a92ec8b1cb989217d114918cc590caa3f7b4455
Reviewed-on: http://gerrit.openafs.org/3716
Tested-by: BuildBot <buildbot@rampaginggeek.com>
Reviewed-by: Derrick Brashear <shadow@dementia.org>