Example: https://build.chromium.org/p/tryserver.chromium.linux/builders/linux_chromium_webkit_variable/builds/49


Recipe failed due to trigger Swarming task twice.
But remote_run ran into exception too, because no recipe result.

---------
Traceback (most recent call last):
  File "../../../scripts/slave/remote_run.py", line 226, in shell_main
    return main(argv)
  File "../../../scripts/slave/remote_run.py", line 211, in main
    with open(recipe_result_path) as f:
IOError: [Errno 2] No such file or directory: '/b/rr/tmp7TNgMQ/recipe_result.json'
---------

It's not a big deal, but kinda hide the real cause at first glance.