Bug#27145 EXTRA_ACL troubles

The flag EXTRA_ACL is used in conjugation with our access checks, yet it is
not clear what impact this flag has.
This is a code clean up which replaces use of EXTRA_ACL with an explicit
function parameter.
The patch also fixes privilege checks for:
- SHOW CREATE TABLE: The new privilege requirement is any privilege on
  the table-level.
- CHECKSUM TABLE: Requires SELECT on the table level.
- SHOW CREATE VIEW: Requires SHOW_VIEW and SELECT on the table level
  (just as the manual claims)
- SHOW INDEX: Requires any privilege on any column combination.

sql/sql_update.cc

@@ -1077,7 +1077,7 @@ reopen_tables:
       if (check_access(thd, want_privilege,
                        tl->db, &tl->grant.privilege, 0, 0, 
                        test(tl->schema_table)) ||
-          check_grant(thd, want_privilege, tl, 0, 1, 0))
+          check_grant(thd, want_privilege, tl, FALSE, 1, FALSE))
         DBUG_RETURN(TRUE);
     }
   }