luci: ramp android-kitkat-arm-rel to 10%.

Formerly known as linux_android_rel_ng.

Bug: 731986
Change-Id: Ib71db01e2d64ac47a647f9916ef3bbcbef32cc0e
Reviewed-on: https://chromium-review.googlesource.com/1069936Reviewed-by: Ben Pastene <bpastene@chromium.org>
Commit-Queue: John Budorick <jbudorick@chromium.org>
Cr-Commit-Position: refs/heads/master@{#562456}

infra/config/branch/cq.cfg

@@ -88,7 +88,11 @@ verifiers {
       }
       builders {
         name: "linux_android_rel_ng"
-        equivalent_to { bucket: "luci.chromium.try" percentage: 0 }
+        equivalent_to {
+          bucket: "luci.chromium.try"
+          builder: "android-kitkat-arm-rel"
+          percentage: 10
+        }
       }
     }
     buckets {