Remove old RULE privilege completely

Hi,

In v8.2, the RULE privilege for tables was removed, but for backward compatibility,
GRANT/REVOKE RULE, has_table_privilege(..., 'RULE') etc are still accepted,
though they don't perform any actions.

Do we still need to maintain this backward compatibility?
Could we consider removing the RULE privilege entirely?

Regards,

-- 
Fujii Masao
Advanced Computing Technology Center
Research and Development Headquarters
NTT DATA CORPORATION