Fix GPU bug
Fix GPU bug

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