[hl][cpp] mysql-sqlite: try..catch can't catch any error request

```haxe
import sys.db.Mysql;
class Test {
static function main() {
var cnx = neko.db.Mysql.connect({
host: "localhost",
port: 3306,
user: "root",
pass: "",
socket: null,
database: "MyBase"
});

try {
cnx.request("select * from noexistTable");//will throw error and crash..
} catch (e:Dynamic) {
trace("can't catch anyting");
}
}
}
```

target:hashlink ,hxcpp