Ticket 475 - Root DN Access Control - improve value checking for config
    
    Bug Description:  Plugin was not checking the time values, and the "allowed-days"
    
    Fix Description:  Make sure the open and close times are with 0000-2359, and make
                      sure that each day in "rootdn-days-allowed" is a valid day.
    
    https://fedorahosted.org/389/ticket/475
    
    Reviewed by: noriko(Thanks!)