Fix to_cpu
Fix to_cpu

hvy/chainer,kikusu/chainer,cupy/cupy,jnishi/chainer,ktnyt/chainer,keisuke-umezawa/chainer,okuta/chainer,ikasumi/chainer,cupy/cupy,ronekko/chainer,ktnyt/chainer,t-abe/chainer,ysekky/chainer,kikusu/chainer,AlpacaDB/chainer,hidenori-t/chainer,ktnyt/chainer,tkerola/chainer,wkentaro/chainer,cupy/cupy,keisuke-umezawa/chainer,sinhrks/chainer,sou81821/chainer,benob/chainer,cupy/cupy,benob/chainer,minhpqn/chainer,wkentaro/chainer,chainer/chainer,hvy/chainer,niboshi/chainer,hvy/chainer,tigerneil/chainer,masia02/chainer,ytoyama/yans_chainer_hackathon,niboshi/chainer,umitanuki/chainer,niboshi/chainer,rezoo/chainer,Kaisuke5/chainer,okuta/chainer,kashif/chainer,chainer/chainer,1986ks/chainer,sinhrks/chainer,kiyukuta/chainer,jnishi/chainer,truongdq/chainer,AlpacaDB/chainer,keisuke-umezawa/chainer,okuta/chainer,jnishi/chainer,niboshi/chainer,hvy/chainer,yanweifu/chainer,cemoody/chainer,t-abe/chainer,tscohen/chainer,wkentaro/chainer,wkentaro/chainer,muupan/chainer,chainer/chainer,delta2323/chainer,chainer/chainer,anaruse/chainer,truongdq/chainer,okuta/chainer,muupan/chainer,aonotas/chainer,jnishi/chainer,keisuke-umezawa/chainer,laysakura/chainer,pfnet/chainer,ktnyt/chainer