rpm: remove postinstall message from openafs-client

rpm: remove postinstall message from openafs-client

Printing out information on how to configure cacheinfo and ThisCell
is a bit noisy, and pam_afs.so is probably not what most people
want to use nowadays.

Reviewed-on: http://gerrit.openafs.org/5026
Reviewed-by: Derrick Brashear <shadow@dementia.org>
Reviewed-by: Simon Wilkinson <sxw@inf.ed.ac.uk>
Tested-by: BuildBot <buildbot@rampaginggeek.com>
(cherry picked from commit 30cd8dafa73d90a943f00af05e4841699bc18534)

Change-Id: Ib6b7448b5e123a593d595b73f8102d82d1ae2535
Reviewed-on: http://gerrit.openafs.org/5203
Reviewed-by: Derrick Brashear <shadow@dementia.org>
Tested-by: BuildBot <buildbot@rampaginggeek.com>