Make afsd.pod reflect reality

Make afsd.pod reflect reality

9d396c4916fdac64fcface30e6637ca6e2911203 (from 2005) introduced
autotuning for afsd, and changed some of the defaults which aren't
autotuned. Update the afsd man page to reflect the autotuning, and
the new defaults.

Change-Id: Iea2035743cb45cca1c249bc2e838405039ad7d3a
Reviewed-on: http://gerrit.openafs.org/744
Tested-by: Derrick Brashear <shadow@dementia.org>
Reviewed-by: Derrick Brashear <shadow@dementia.org>
(cherry picked from commit 7833e472b9585ee1a7085ca704e642a73ca969a5)
Reviewed-on: http://gerrit.openafs.org/773