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/60cc7f3f49737e8cf852e396b4436c2b6bd3f56d Add vpython support to Python recipe module. (dnj@chromium.org)
  https://crrev.com/c6560f3627af81c9004024079525ef63a223d33a Add "url" recipe module to base. (dnj@chromium.org)


TBR=iannucci@chromium.org

Recipe-Tryjob-Bypass-Reason: Autoroller
Bugdroid-Send-Email: False
Change-Id: Iecc732789febe840a4fe42374d8264f5e9ea0f06
Reviewed-on: https://chromium-review.googlesource.com/504967
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": "b7c18e0258998652eeb302c83680f6a2b1aee398",
+      "revision": "c6560f3627af81c9004024079525ef63a223d33a",
       "url": "https://chromium.googlesource.com/external/github.com/luci/recipes-py.git"
     }
   },