Remove unused section in build file.

Bug: 812974
Change-Id: If3b39236ddc753f8ef3f8caab4b8c2a5b12497fd
Reviewed-on: https://chromium-review.googlesource.com/988799
Commit-Queue: Fabrice de Gans-Riberi <fdegans@chromium.org>
Commit-Queue: Sergey Ulanov <sergeyu@chromium.org>
Reviewed-by: Sergey Ulanov <sergeyu@chromium.org>
Reviewed-by: Tommi <tommi@chromium.org>
Cr-Commit-Position: refs/heads/master@{#548273}