Simplify the identity initializer
Simplify the identity initializer

okuta/chainer,jnishi/chainer,ysekky/chainer,jnishi/chainer,keisuke-umezawa/chainer,niboshi/chainer,jnishi/chainer,rezoo/chainer,aonotas/chainer,delta2323/chainer,okuta/chainer,okuta/chainer,chainer/chainer,ronekko/chainer,cupy/cupy,kashif/chainer,hvy/chainer,hvy/chainer,ktnyt/chainer,keisuke-umezawa/chainer,wkentaro/chainer,anaruse/chainer,jnishi/chainer,keisuke-umezawa/chainer,hvy/chainer,hvy/chainer,kiyukuta/chainer,tkerola/chainer,wkentaro/chainer,pfnet/chainer,niboshi/chainer,chainer/chainer,chainer/chainer,ktnyt/chainer,chainer/chainer,okuta/chainer,wkentaro/chainer,cupy/cupy,cupy/cupy,niboshi/chainer,niboshi/chainer,wkentaro/chainer,ktnyt/chainer,keisuke-umezawa/chainer,ktnyt/chainer,cupy/cupy