[autoscaler] Fix Error Handling for botocore (#3534)
[autoscaler] Fix Error Handling for botocore (#3534)

Unfortunately Boto generates error classes dynamically, so this catches
the expected error and raises the error if it is the wrong class.

Closes #3533. 
atumanov/ray,atumanov/ray,robertnishihara/ray,pcmoritz/ray-1,pcmoritz/ray-1,stephanie-wang/ray,ray-project/ray,ujvl/ray-ng,ray-project/ray,richardliaw/ray,pcmoritz/ray-1,robertnishihara/ray,robertnishihara/ray,ujvl/ray-ng,ujvl/ray-ng,atumanov/ray,richardliaw/ray,ray-project/ray,ray-project/ray,stephanie-wang/ray,stephanie-wang/ray,robertnishihara/ray,richardliaw/ray,ray-project/ray,pcmoritz/ray-1,robertnishihara/ray,robertnishihara/ray,richardliaw/ray,atumanov/ray,pcmoritz/ray-1,ray-project/ray,stephanie-wang/ray,richardliaw/ray,atumanov/ray,richardliaw/ray,ray-project/ray,pcmoritz/ray-1,stephanie-wang/ray,richardliaw/ray,stephanie-wang/ray,robertnishihara/ray,stephanie-wang/ray,pcmoritz/ray-1,pcmoritz/ray-1,robertnishihara/ray,ujvl/ray-ng,atumanov/ray,stephanie-wang/ray,atumanov/ray,robertnishihara/ray,atumanov/ray,ray-project/ray,stephanie-wang/ray,richardliaw/ray