[SSSD] [sssd PR#921][opened] util/server.c: fix handling when error occurs in waitpid()

[miztake]

URL: https://github.com/SSSD/sssd/pull/921
Author: miztake
 Title: #921: util/server.c: fix handling when error occurs in waitpid()
Action: opened

PR body:
"""
-1 is returned if an error occurs in waitpid().
Fixed inappropriate error handling.
"""

To pull the PR as Git branch:
git remote add ghsssd https://github.com/SSSD/sssd
git fetch ghsssd pull/921/head:pr921
git checkout pr921