Fix a bug in sequence_erase_op
Fix a bug in sequence_erase_op

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