Fix Travis-CI build error.
Fix Travis-CI build error.

* error because merge of #711. The old issue don't check pre-commit
  hooks.

jacquesqiao/Paddle,zhouxiao-coder/Paddle,luotao1/Paddle,emailweixu/Paddle,lispc/Paddle,emailweixu/Paddle,zhouxiao-coder/Paddle,hedaoyuan/Paddle,zhouxiao-coder/Paddle,zhouxiao-coder/Paddle,cxysteven/Paddle,dayhaha/Paddle,yu239/Paddle,cxysteven/Paddle,baidu/Paddle,chengduoZH/Paddle,luotao1/Paddle,lcy-seso/Paddle,Canpio/Paddle,yu239/Paddle,cxysteven/Paddle,PaddlePaddle/Paddle,QiJune/Paddle,livc/Paddle,hedaoyuan/Paddle,yu239/Paddle,yu239/Paddle,hedaoyuan/Paddle,lispc/Paddle,livc/Paddle,tensor-tang/Paddle,hedaoyuan/Paddle,PaddlePaddle/Paddle,QiJune/Paddle,cxysteven/Paddle,PaddlePaddle/Paddle,jacquesqiao/Paddle,PaddlePaddle/Paddle,chengduoZH/Paddle,pengli09/Paddle,tensor-tang/Paddle,livc/Paddle,emailweixu/Paddle,pkuyym/Paddle,beckett1124/Paddle,Canpio/Paddle,lcy-seso/Paddle,cxysteven/Paddle,livc/Paddle,jacquesqiao/Paddle,lcy-seso/Paddle,reyoung/Paddle,emailweixu/Paddle,beckett1124/Paddle,livc/Paddle,reyoung/Paddle,wen-bo-yang/Paddle,lispc/Paddle,QiJune/Paddle,dayhaha/Paddle,pkuyym/Paddle,gangliao/Paddle,putcn/Paddle,wen-bo-yang/Paddle,baidu/Paddle,dayhaha/Paddle,reyoung/Paddle,QiJune/Paddle,dayhaha/Paddle,lispc/Paddle,Canpio/Paddle,hedaoyuan/Paddle,luotao1/Paddle,emailweixu/Paddle,jacquesqiao/Paddle,putcn/Paddle,pengli09/Paddle,wen-bo-yang/Paddle,gangliao/Paddle,pengli09/Paddle,yu239/Paddle,pengli09/Paddle,dayhaha/Paddle,luotao1/Paddle,pkuyym/Paddle,gangliao/Paddle,zhouxiao-coder/Paddle,lispc/Paddle,jacquesqiao/Paddle,yu239/Paddle,lispc/Paddle,livc/Paddle,lispc/Paddle,hedaoyuan/Paddle,yu239/Paddle,luotao1/Paddle,emailweixu/Paddle,PaddlePaddle/Paddle,Canpio/Paddle,tensor-tang/Paddle,reyoung/Paddle,wen-bo-yang/Paddle,beckett1124/Paddle,emailweixu/Paddle,putcn/Paddle,chengduoZH/Paddle,reyoung/Paddle,hedaoyuan/Paddle,chengduoZH/Paddle,dayhaha/Paddle,lispc/Paddle,Canpio/Paddle,lcy-seso/Paddle,lcy-seso/Paddle,Canpio/Paddle,QiJune/Paddle,chengduoZH/Paddle,putcn/Paddle,beckett1124/Paddle,Canpio/Paddle,reyoung/Paddle,pengli09/Paddle,jacquesqiao/Paddle,gangliao/Paddle,baidu/Paddle,PaddlePaddle/Paddle,cxysteven/Paddle,PaddlePaddle/Paddle,zhouxiao-coder/Paddle,luotao1/Paddle,baidu/Paddle,luotao1/Paddle,beckett1124/Paddle,QiJune/Paddle,pkuyym/Paddle,putcn/Paddle,pengli09/Paddle,pkuyym/Paddle,gangliao/Paddle,gangliao/Paddle,putcn/Paddle,hedaoyuan/Paddle,wen-bo-yang/Paddle,pengli09/Paddle,Canpio/Paddle,pkuyym/Paddle,tensor-tang/Paddle,livc/Paddle,gangliao/Paddle,cxysteven/Paddle,zhouxiao-coder/Paddle,tensor-tang/Paddle,dayhaha/Paddle,wen-bo-yang/Paddle,beckett1124/Paddle,wen-bo-yang/Paddle,pengli09/Paddle,lcy-seso/Paddle,baidu/Paddle,yu239/Paddle,beckett1124/Paddle