Handle upgrade issues with systemd in Fedora 16 and above
    
    Since 389-ds-base-1.2.10-0.8.a7 Directory Server's systemd settings are
    configured via /etc/sysconfig/dirsrv.systemd. It means logic change in
    systemd/fedora16 platform of FreeIPA.
    
    Additionally, existing installs need to be handled during upgrade.
    
    Fixes:
        https://fedorahosted.org/freeipa/ticket/2117
        https://fedorahosted.org/freeipa/ticket/2300