With this change, both 'SET @my_id = (SELECT LAST_INSERT_ID())' and
'SET @my_id = (SELECT @@LAST_INSERT_ID)' are classified as
QUERY_TYPE_MASTER_READ|QUERY_TYPE_SESSION_WRITE|QUERY_TYPE_USERVAR_WRITE
Earlier @@last_insert_id had the QUERY_TYPE_READ bit set as well, which
indirectly caused the problems of MXS-2898.