Ticket 16 - with systemd should unset have systemd if pkgconfig not found
    
    Bug Description:  On platforms that don't have systemd, we should check for this
    and correctly disable the systemd parts of svrcore.
    
    Fix Description:  Add pkgconfig check to configure that will automatically
    disable systemd support if the pc file is not found.
    
    https://pagure.io/svrcore/issue/16
    
    Author: wibrown
    
    Review by: lslebodn