Fix QPO timeout overflow

[alpes214]

Description:
Fixes integer overflow for query rules timeout

Verification:

1. Set query rules with timeout value equals to one hour.

INSERT INTO mysql_query_rules (rule_id,active,match_digest,destination_hostgroup,timeout,apply) VALUES (1,1,'^SELECT.*FOR UPDATE$',0,3600*1000,1), (2,1,'^SELECT',1,3600*1000,1);
load mysql query rules to runtime; save mysql query rules to disk;

2. Execute query

$ time mysql -uroot -proot -h127.0.0.1 -P6033 -e "select 1, sleep(3601)"
mysql: [Warning] Using a password on the command line interface can be insecure.
+---+-------------+
| 1 | sleep(3601) |
+---+-------------+
| 1 |           1 |
+---+-------------+

real    60m0.013s
user    0m0.012s
sys     0m0.000s

The query ended as expected after 1 hour.