Fix the simulated bug behaviour of packbits
Fix the simulated bug behaviour of packbits

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