Keep FunctionNode output count for output_data
Keep FunctionNode output count for output_data

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