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.
recipe_engine:
  https://crrev.com/8d7bd42ec1713294cf6cb36127c96a1f439f9419 Enable unbuffered output for bundled recipes. (benjaminwagner@google.com)


TBR=iannucci@chromium.org

Recipe-Tryjob-Bypass-Reason: Autoroller
Bugdroid-Send-Email: False
Change-Id: I13297698e934ae231178838d2e74e02044646afd
Reviewed-on: https://chromium-review.googlesource.com/519824Reviewed-by: Recipe Roller <recipe-roller@chromium.org>
Commit-Queue: Recipe Roller <recipe-roller@chromium.org>

infra/config/recipes.cfg

@@ -15,7 +15,7 @@
   "deps": {
     "recipe_engine": {
       "branch": "master",
-      "revision": "84a695b241eb61b3b6d1a0fa9d63ef572d26cdbd",
+      "revision": "8d7bd42ec1713294cf6cb36127c96a1f439f9419",
       "url": "https://chromium.googlesource.com/external/github.com/luci/recipes-py.git"
     }
   },