data: use new g-s-d's plugin whitelist
    
    GDM tries to manually turn off unvetted or unwanted
    gnome-settings-daemon plugins explicitly.  This requires
    close coordination between gdm and gnome-settings-daemon to
    make sure the lists down get out of sync.
    
    gnome-settings-daemon now supports having an explicit whitelist,
    which is a much more robust way to handle our needs.
    
    This commit changes GDM's dconf configuration to use the new whitelist
    setting, instead of expliciting turning off each unwanted plugin.
    
    https://bugzilla.gnome.org/show_bug.cgi?id=662220