fix producer callback function

[xuxiaoahang2018]

1. 修复producer 回调函数打印为空的问题。

该问题会由以下两种情况下出现：
(1). 程序启动就错误，发送数据量非常少。因为producer异步发送，在消息未被发送时，已经接收到了retry关闭信号，这时候没有去给producerBatch 添加attemp 信息。
(2). 遇到特定的错误码，没有给producerBatch 添加attemp 信息，例如 ProjectNotExist等 .

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[shabicheng]

/LGTM