Revert changes to link.py
Revert changes to link.py

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