[SSSD] [sssd PR#916][opened] Fix one coverity issue

[alexey-tikhonov]

   URL: https://github.com/SSSD/sssd/pull/916
Author: alexey-tikhonov
 Title: #916: Fix one coverity issue
Action: opened

PR body:
"""
...and reduce code duplication a little bit.
"""

To pull the PR as Git branch:
git remote add ghsssd https://github.com/SSSD/sssd
git fetch ghsssd pull/916/head:pr916
git checkout pr916