Fix forward method in Link
Fix forward method in Link

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