Ticket 47951 - Fix startpid from altering dev/null
    
    Bug Description:  If startpid (-w) was not added to the server, Ds would change
    attributes of dev/null
    
    Fix Description:  Remove the hardcoded /dev/null, and do a proper check for
    if the start pid should be written.
    
    https://fedorahosted.org/389/ticket/47951
    
    Author: wibrown
    
    Review by: lkrispen (Thanks!)