Ticket 48450 - Systemd password agent support
    
    Bug Description:  Directory server needs to be able to prompt for passwords with
    with systemd during systemd startup, or post start up.
    
    Fix Description:  This allows Directory Server to take advantage of the svrcore
    systemd integration, allowing systemd password as the "last resport" if file
    or tty is not avaliable to the administrator.
    
    https://fedorahosted.org/389/ticket/48450
    
    Author: wibrown
    
    Review by: nhosoi (Thanks!)