Remove Rietveld CQ config.

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

R=agable@chromium.org
TBR=sergiyb@chromium.org

No-Try: True
Bug: chromium:770592
Change-Id: Ic992d2b85c4108a181d786304030e00a5e6b3b58
Reviewed-on: https://chromium-review.googlesource.com/714304
Reviewed-by: Andrii Shyshkalov <tandrii@chromium.org>
Reviewed-by: Sergiy Byelozyorov <sergiyb@chromium.org>
Commit-Queue: Andrii Shyshkalov <tandrii@chromium.org>
Cr-Commit-Position: refs/heads/master@{#508365}

infra/config/cq.cfg

@@ -9,16 +9,8 @@ commit_burst_delay: 60
 max_commit_burst: 2
 
 gerrit {}
-rietveld {
-  url: "https://codereview.chromium.org"
-}
 
 verifiers {
-  reviewer_lgtm {
-    committer_list: "project-chromium-committers"
-    dry_run_access_list: "project-chromium-tryjob-access"
-  }
-
   gerrit_cq_ability {
     committer_list: "project-chromium-committers"
     dry_run_access_list: "project-chromium-tryjob-access"