Deprecate kpropd -S option

https://github.com/krb5/krb5/commit/54d4ec82e2a236dc7cfd3f0b52534b14dd51c6a0
Author: Nicolas Williams <nico@cryptonector.com>
Committer: Greg Hudson <ghudson@mit.edu>
Commit: 54d4ec82e2a236dc7cfd3f0b52534b14dd51c6a0
Branch: master
 .../krb_admins/admin_commands/kpropd.rst           |   10 +++++-----
 src/slave/kpropd.c                                 |   13 ++++++++++++-
 2 files changed, 17 insertions(+), 6 deletions(-)