Add error 1290/ER_READ_ONLY_MODE to rejectReadOnly handling (#1660)

Author: kolbe

packets.go

@@ -574,7 +574,8 @@ func (mc *mysqlConn) handleErrorPacket(data []byte) error {
 
 	// 1792: ER_CANT_EXECUTE_IN_READ_ONLY_TRANSACTION
 	// 1290: ER_OPTION_PREVENTS_STATEMENT (returned by Aurora during failover)
-	if (errno == 1792 || errno == 1290) && mc.cfg.RejectReadOnly {
+	// 1836: ER_READ_ONLY_MODE
+	if (errno == 1792 || errno == 1290 || errno == 1836) && mc.cfg.RejectReadOnly {
 		// Oops; we are connected to a read-only connection, and won't be able
 		// to issue any write statements. Since RejectReadOnly is configured,
 		// we throw away this connection hoping this one would have write