Roll recipe dependencies (trivial).

This is an automated CL created by the recipe roller. This CL rolls recipe
changes from upstream projects (e.g. depot_tools) into downstream projects
(e.g. tools/build).


More info is at https://goo.gl/zkKdpD. Use https://goo.gl/noib3a to file a bug
(or complain)

recipe_engine:
  https://crrev.com/855168108b3dab668c36b56a99ca5a73f6d98932 [recipes.cfg] upgrade to api_version 2 (iannucci@chromium.org)

TBR=iannucci@chromium.org

Change-Id: I4e361cd1afeeac49c9fba7467834ea840b71e1ce
Recipe-Tryjob-Bypass-Reason: Autoroller
Bugdroid-Send-Email: False
Reviewed-on: https://chromium-review.googlesource.com/462615
Reviewed-by: <recipe-roller@chromium.org>
Commit-Queue: <recipe-roller@chromium.org>

infra/config/recipes.cfg

@@ -4,7 +4,7 @@
     {
       "branch": "master",
       "project_id": "recipe_engine",
-      "revision": "9f7465ffe92dab0bcc6f4d0e60303c6bff4d0f72",
+      "revision": "855168108b3dab668c36b56a99ca5a73f6d98932",
       "url": "https://chromium.googlesource.com/external/github.com/luci/recipes-py.git"
     }
   ],