[SSSD] [sssd PR#295][synchronized] MAN: Document that the secrets provider can only be specified in a per-client section

[jhrozek]

   URL: https://github.com/SSSD/sssd/pull/295
Author: jhrozek
 Title: #295: MAN: Document that the secrets provider can only be specified in a
per-client section
Action: synchronized

To pull the PR as Git branch:
git remote add ghsssd https://github.com/SSSD/sssd
git fetch ghsssd pull/295/head:pr295
git checkout pr295