Add more owners to src/services

Change-Id: I9abfb441a9c0de36bc91975b39a5b48568c356a1
Reviewed-on: https://chromium-review.googlesource.com/565543Reviewed-by: Ken Rockot <rockot@chromium.org>
Commit-Queue: John Abd-El-Malek <jam@chromium.org>
Cr-Commit-Position: refs/heads/master@{#485305}

services/OWNERS

 ben@chromium.org
+blundell@chromium.org
 jam@chromium.org
 rockot@chromium.org
+sky@chromium.org
+yzshen@chromium.org