Drain CQ for all CLs submitted to CQ after 12pm today.

No CLs submitted after that time to CQ will be procesed until
this CL is reverted.

R=iannucci@chromium.org, jchinlee@chromium.org

Bug: 817498
Change-Id: I9e0f8a542cff370013d46166f12d5e81b3c1c58c
No-Try: True
Reviewed-on: https://chromium-review.googlesource.com/941967Reviewed-by: Jao-ke Chin-Lee <jchinlee@chromium.org>
Cr-Commit-Position: refs/heads/master@{#539942}

infra/config/branch/cq.cfg

@@ -8,6 +8,9 @@ git_repo_url: "https://chromium.googlesource.com/chromium/src"
 commit_burst_delay: 60
 max_commit_burst: 2
 
+# TODO(tAandrii): remove this after outage of crbug/817498 is over.
+draining_start_time: "2018-02-28T20:00:00Z"  # 12PM PST(MTV) time.
+
 gerrit {}
 
 verifiers {