redhat: fix rpmbuild command line option defaults
Fix the handling of default values for the various rpmbuild options
which can be given. These have been broken as code was shuffled around
over the years.
Remove obsolete comments about detecting what to build based on the
architecture.
Provide the '--without authlibs' option to disable the openafs-authlibs
package.
Change-Id: I6c8db1f3163ee241f9a4d1282345a0ddeabd284c
Reviewed-on: https://gerrit.openafs.org/12596
Reviewed-by: Stephan Wiesand <stephan.wiesand@desy.de>
Reviewed-by: Michael Meffie <mmeffie@sinenomine.net>
Reviewed-by: Benjamin Kaduk <kaduk@mit.edu>
Tested-by: Benjamin Kaduk <kaduk@mit.edu>