Remove Rietveld CQ config.

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

TBR=kjellander@webrtc.org

No-Try: True
Bug: chromium:770592
Change-Id: I893d7a4be9a22ece16fc7547549143d480174bcb
Reviewed-on: https://webrtc-review.googlesource.com/8780
Reviewed-by: Henrik Kjellander <kjellander@webrtc.org>
Commit-Queue: Andrii Shyshkalov <tandrii@chromium.org>
Cr-Commit-Position: refs/heads/master@{#20255}

infra/config/cq.cfg

diff --git a/infra/config/cq.cfg b/infra/config/cq.cfg
index 669e4d5..674b7f7 100644
--- a/infra/config/cq.cfg
+++ b/infra/config/cq.cfg
@@ -9,17 +9,8 @@
 max_commit_burst: 1
 
 gerrit {}
-rietveld {
-  url: "https://codereview.webrtc.org"
-}
-
 
 verifiers {
-  reviewer_lgtm {
-    committer_list: "project-webrtc-committers"
-    dry_run_access_list: "project-webrtc-tryjob-access"
-  }
-
   gerrit_cq_ability {
     committer_list: "project-webrtc-committers"
     dry_run_access_list: "project-webrtc-tryjob-access"