SDAP: Improve a DEBUG message about GC detection
    
    It was not entirely clear what the message means. We should improve the
    debug message to make it clear that all or none attributes should be
    replicated to the Global Catalog.
    
    This patch can be reverted once we fix
    https://pagure.io/SSSD/sssd/issue/3538 and only use the GC to look up
    the entry DN, not the entry itself.
    
    Reviewed-by: Fabiano Fidêncio <fidencio@redhat.com>