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/a8d7f3279c321895575723d7e56e5798fd34b9bb Use "vpython" to bootstrap the recipe engine. (dnj@chromium.org)


TBR=iannucci@chromium.org

Recipe-Tryjob-Bypass-Reason: Autoroller
Bugdroid-Send-Email: False
Change-Id: I0536777e590f7245fd3702fe018644bb7e26e64a
Reviewed-on: https://chromium-review.googlesource.com/490768
Reviewed-by: <recipe-roller@chromium.org>
Commit-Queue: <recipe-roller@chromium.org>

infra/config/recipes.cfg

@@ -15,7 +15,7 @@
   "deps": {
     "recipe_engine": {
       "branch": "master",
-      "revision": "0fa4d3588d8cb91e8da2247418b68a228a090891",
+      "revision": "a8d7f3279c321895575723d7e56e5798fd34b9bb",
       "url": "https://chromium.googlesource.com/external/github.com/luci/recipes-py.git"
     }
   },