Fix wrong eval_size
Fix wrong eval_size

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