fix mysql::prepare bugs.
fix mysql::prepare bugs.

swoole/swoole-src,swoole/swoole-src,LinkedDestiny/swoole-src,swoole/swoole-src,LinkedDestiny/swoole-src,LinkedDestiny/swoole-src,LinkedDestiny/swoole-src,LinkedDestiny/swoole-src,swoole/swoole-src,LinkedDestiny/swoole-src,swoole/swoole-src,LinkedDestiny/swoole-src,swoole/swoole-src,swoole/swoole-src