fix the build of the doc.
fix the build of the doc.

QiJune/Paddle,tensor-tang/Paddle,chengduoZH/Paddle,PaddlePaddle/Paddle,PaddlePaddle/Paddle,tensor-tang/Paddle,lcy-seso/Paddle,tensor-tang/Paddle,pkuyym/Paddle,luotao1/Paddle,jacquesqiao/Paddle,lcy-seso/Paddle,putcn/Paddle,baidu/Paddle,PaddlePaddle/Paddle,PaddlePaddle/Paddle,chengduoZH/Paddle,putcn/Paddle,chengduoZH/Paddle,PaddlePaddle/Paddle,putcn/Paddle,Canpio/Paddle,luotao1/Paddle,QiJune/Paddle,reyoung/Paddle,jacquesqiao/Paddle,PaddlePaddle/Paddle,reyoung/Paddle,QiJune/Paddle,baidu/Paddle,Canpio/Paddle,luotao1/Paddle,pkuyym/Paddle,chengduoZH/Paddle,reyoung/Paddle,lcy-seso/Paddle,baidu/Paddle,jacquesqiao/Paddle,baidu/Paddle,pkuyym/Paddle,luotao1/Paddle,luotao1/Paddle,jacquesqiao/Paddle,pkuyym/Paddle,tensor-tang/Paddle,luotao1/Paddle,Canpio/Paddle,pkuyym/Paddle,pkuyym/Paddle,lcy-seso/Paddle,Canpio/Paddle,chengduoZH/Paddle,QiJune/Paddle,tensor-tang/Paddle,Canpio/Paddle,luotao1/Paddle,Canpio/Paddle,putcn/Paddle,reyoung/Paddle,lcy-seso/Paddle,jacquesqiao/Paddle,reyoung/Paddle,putcn/Paddle,lcy-seso/Paddle,jacquesqiao/Paddle,putcn/Paddle,QiJune/Paddle,Canpio/Paddle,Canpio/Paddle,baidu/Paddle,reyoung/Paddle,QiJune/Paddle,PaddlePaddle/Paddle