Ticket 48747 - dirsrv service fails to start when nsslapd-listenhost is configured
    
    Bug Description:
    In some environments network initialization takes a long time (slow DHCP, etc).
    When nsslapd-listenhost is configured, dirsrv systemd service fails to start,
    because it doesn't wait for the network to be available.
    
    Fix Description:
    Make dirsrv@.service wait for network.service
    
    https://fedorahosted.org/389/ticket/48747
    
    Reviewed by nhosoi@redhat.com.