Remove Rietveld CQ config.
Remove Rietveld CQ config.

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

R=bbed39beedae4cdb499af742d2fcd6c63934d93b@chromium.org

No-Try: True
Bug: 770592
Change-Id: I187da15a52fbb7573be31b5ea5065dceb7ed474a
Reviewed-on: https://chromium-review.googlesource.com/714486
Reviewed-by: Aaron Gable <bbed39beedae4cdb499af742d2fcd6c63934d93b@chromium.org>
Commit-Queue: Andrii Shyshkalov <a30c74fa30536fe7ea81ed6dec202e35e149e1fd@chromium.org>

luci/luci-go,luci/luci-go,luci/luci-go,luci/luci-go,luci/luci-go,luci/luci-go