Fix CUDA specific Python binding
Fix CUDA specific Python binding

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