Simplify about on_rtd flag
Simplify about on_rtd flag

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