[SSSD] [PATCH] Set cloexec flag for log files

[Jakub Hrozek]

https://fedorahosted.org/sssd/ticket/1708

The services kept the fd to /var/log/sssd/sssd.log open. I don't think
there's any point in keeping the logfiles open after exec-ing for the
child, so I set the CLOEXEC flag.