Fix error message
Fix error message

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