Fix double delete a pointer.
Fix double delete a pointer.

lizhanhui/rocketmq-client4cpp,lizhanhui/rocketmq-client4cpp,NDPMediaCorp/RocketMQ-Client4CPP,lizhanhui/rocketmq-client4cpp,NDPMediaCorp/RocketMQ-Client4CPP,NDPMediaCorp/RocketMQ-Client4CPP,NDPMediaCorp/RocketMQ-Client4CPP,NDPMediaCorp/RocketMQ-Client4CPP,lizhanhui/rocketmq-client4cpp,lizhanhui/rocketmq-client4cpp