Fix initialization of self.flush
Fix initialization of self.flush

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