Add ssid to leveldb_proto OWNERS

Change-Id: I014c9f549e8ef65782590056ad3dbe5722bb7d24
Reviewed-on: https://chromium-review.googlesource.com/c/1471954Reviewed-by: Tommy Nyquist <nyquist@chromium.org>
Commit-Queue: ssid <ssid@chromium.org>
Cr-Commit-Position: refs/heads/master@{#632656}

components/leveldb_proto/OWNERS

 mathp@chromium.org
 nyquist@chromium.org
+ssid@chromium.org
 
 # COMPONENT: Internals