Ticket 47968 - When systemd libs not found, error instead of continuing.
    
    Bug Description:  Systemd-devel isn't installed, we still build and weird
    things happen.
    
    Fix Description:  Make sure to error if we have --with-systemd and no
    systemd-devel package
    
    https://fedorahosted.org/389/ticket/47968
    
    Author: wibrown
    
    Review by: One line patch