[SSSD] [sssd PR#554][synchronized] Several fixes for the files provider

[jhrozek]

   URL: https://github.com/SSSD/sssd/pull/554
Author: jhrozek
 Title: #554: Several fixes for the files provider
Action: synchronized

To pull the PR as Git branch:
git remote add ghsssd https://github.com/SSSD/sssd
git fetch ghsssd pull/554/head:pr554
git checkout pr554