remove redundant device allocation.
remove redundant device allocation.

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