MySQL TIME类型字段，值为负数-00:00:00.12时解析的值错误，解析为正数00:00:00.12，负号丢掉了

[clanmaps]

• I have searched the issues of this repository and believe that this is not a duplicate.
• I have checked the FAQ of this repository and believe that this is not a duplicate.

environment

• canal version v1.1.5
• mysql version 5.7.23

Issue Description

MySQL字段类型为TIME时，写入值-00:00:00.12，canal解析出来的值变成了正数00:00:00.12。只有当时分秒都为0，并且毫秒值为负数时才会触发该问题。
看了下代码，应该是RowsLogBuffer解析的bug，第735行，判断正数部分为0后生成时间前缀"00:00:00"，感觉应该同时判断下毫秒值，毫秒为负数时前缀需要加上负号：

String second = null;
    if (intpart == 0) {
        second = frac < 0 ? "-00:00:00" : "00:00:00";
    } else {

原代码如下：

String second = null;
    if (intpart == 0) {
        second = "00:00:00";
    } else {

Steps to reproduce

建表语句如下：

CREATE DATABASE if not exists canal;
CREATE TABLE `canal`.`time2` (
    `id` int(11) NOT NULL AUTO_INCREMENT,
    `start_time` TIME(2) NOT NULL COMMENT '时间',
    PRIMARY KEY (`id`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4 COMMENT='time2测试表';

执行如下SQL写入数据：

insert into canal.time2(start_time) value('-00:00:00.12');

Expected behaviour

canal可以正确解析出start_time负数字段值-00:00:00.12

Actual behaviour

实际上canal解析出来的start_time字段值变成了正数00:00:00.12，负号丢掉了

[agapple]

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