Remove duplicate CREATE_SGUID_ADMIN_ONLY define

A trivial omission from 30433f36a953187f27b5db9fb432f3b7dce91e6b

Change-Id: If85ebd73a68c6226077b690243a94c2e40f88149
Reviewed-on: http://gerrit.openafs.org/11556
Tested-by: BuildBot <buildbot@rampaginggeek.com>
Reviewed-by: Jeffrey Altman <jaltman@your-file-system.com>