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)

build:
  https://crrev.com/cad2afbfe798451f2b0bad1b379d14ff9f8c3577 WebRTC: Fallback for working_dir in symlink cleaning (kjellander@chromium.org)

TBR=martiniss@chromium.org,phajdan.jr@chromium.org

Recipe-Tryjob-Bypass-Reason: Autoroller
Bugdroid-Send-Email: False
Review-Url: https://codereview.chromium.org/2490133002
Cr-Commit-Position: refs/heads/master@{#431211}

infra/config/recipes.cfg

@@ -5,7 +5,7 @@ deps {
   project_id: "build"
   url: "https://chromium.googlesource.com/chromium/tools/build.git"
   branch: "master"
-  revision: "bac681250e8cb2f4e17ae68dca934d127d3e0b0f"
+  revision: "cad2afbfe798451f2b0bad1b379d14ff9f8c3577"
 }
 deps {
   project_id: "depot_tools"