Fix spelling error
Fix spelling error

chainer/chainer,hvy/chainer,wkentaro/chainer,chainer/chainer,pfnet/chainer,wkentaro/chainer,chainer/chainer,keisuke-umezawa/chainer,wkentaro/chainer,okuta/chainer,niboshi/chainer,niboshi/chainer,okuta/chainer,chainer/chainer,niboshi/chainer,keisuke-umezawa/chainer,wkentaro/chainer,hvy/chainer,okuta/chainer,keisuke-umezawa/chainer,okuta/chainer,keisuke-umezawa/chainer,hvy/chainer,tkerola/chainer,hvy/chainer,niboshi/chainer