incorrect isolation level in update with unique using hash or without overlap

--source include/have_innodb.inc

create table t1 (id int, e varchar(100), a int, unique (e) using hash) engine=innodb;

insert t1 values(10, '2000-01-01', 0);

insert t1 values(20, '2000-01-02', 1);

insert t1 values(30, '2000-01-03', 2);

set transaction isolation level read committed;

start transaction;

update t1 set a=10 where a=0;

--connect con1,localhost,root

set transaction isolation level read committed;

update t1 set a=20 where a=1;

connection default;

drop table t1;