Switch to BLS in tools package %post scriptlet
    
    The switch to a BLS configuration was made before in the grubby package
    %post scriptlet, but this is wrong since it means that a not up-do-date
    grub2-switch-to-blscfg script could be used to do the switch.
    
    Resolves: rhbz#1652806
    
    Signed-off-by: Javier Martinez Canillas <javierm@redhat.com>