Rietveld CQ has already been disabled and is no longer supoorted.

TBR=iannucci@chromium.org

No-Try: True
Bug: 770592
Change-Id: I35b0c6c9da585519b9ad6df316709fb58b17b24f
Reviewed-on: https://chromium-review.googlesource.com/714298Reviewed-by: Andrii Shyshkalov <tandrii@chromium.org>
Commit-Queue: Andrii Shyshkalov <tandrii@chromium.org>