[rllib] Queue lib for python 2.7 (#2057)
[rllib] Queue lib for python 2.7 (#2057)

* Queue lib for python 2.7

* use six.moves.queue instead

stephanie-wang/ray,atumanov/ray,stephanie-wang/ray,richardliaw/ray,pcmoritz/ray-1,pcmoritz/ray-1,stephanie-wang/ray,ujvl/ray-ng,robertnishihara/ray,atumanov/ray,ray-project/ray,robertnishihara/ray,robertnishihara/ray,ray-project/ray,richardliaw/ray,stephanie-wang/ray,stephanie-wang/ray,atumanov/ray,richardliaw/ray,stephanie-wang/ray,ray-project/ray,pcmoritz/ray-1,stephanie-wang/ray,ujvl/ray-ng,stephanie-wang/ray,pcmoritz/ray-1,robertnishihara/ray,atumanov/ray,ujvl/ray-ng,ray-project/ray,richardliaw/ray,robertnishihara/ray,robertnishihara/ray,richardliaw/ray,atumanov/ray,atumanov/ray,atumanov/ray,pcmoritz/ray-1,atumanov/ray,robertnishihara/ray,ujvl/ray-ng,richardliaw/ray,richardliaw/ray,pcmoritz/ray-1,robertnishihara/ray,pcmoritz/ray-1,ray-project/ray,pcmoritz/ray-1,robertnishihara/ray,ray-project/ray,ray-project/ray,richardliaw/ray,ray-project/ray,stephanie-wang/ray