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/4afdf69bc15cbcf6a88076da7074d24cb88780d2 Add test coverage for testing recipe configs and test_api (phajdan.jr@chromium.org)

TBR=iannucci@chromium.org

Change-Id: Ia28a35f38794ae2baae3b29a58594eb67b6647b6
Recipe-Tryjob-Bypass-Reason: Autoroller
Bugdroid-Send-Email: False
Reviewed-on: https://chromium-review.googlesource.com/473927
Reviewed-by: <recipe-roller@chromium.org>
Commit-Queue: <recipe-roller@chromium.org>

infra/config/recipes.cfg

@@ -3,10 +3,10 @@
   "deps": {
     "recipe_engine": {
       "branch": "master",
-      "revision": "4e482d2131c51fd19f9a3e8840ae74c52a7b6567",
+      "revision": "4afdf69bc15cbcf6a88076da7074d24cb88780d2",
       "url": "https://chromium.googlesource.com/external/github.com/luci/recipes-py.git"
     }
   },
   "project_id": "depot_tools",
   "recipes_path": "recipes"
-}
+}
\ No newline at end of file