Remove GRUB Legacy support
    
    GRUB Legacy is retired since Fedora 19, hence its support can be
    removed.
    
    This brings a noticeable simplification of memtest-setup script. The
    new-memtest-pkg script is only tied to GRUB Legacy, so it's no longer
    needed. Without this script, grubby and util-linux dependencies can
    also be removed.
    
    The memtest-setup man page didn't contain all available options and
    also referred to GRUB Legacy, hence it's completely rewritten. The new
    man page is also used as a template for memtest-setup help message.
    
    Signed-off-by: Jan Hlavac <jhlavac@redhat.com>