gerrit: use "change:change-id" when querying using Change-Id

Without the "change:" prefix, Gerrit may return multiple CLs.

BUG=chromium:358758
TEST=`buildbot/run_tests` passes

Change-Id: Idfa979e266078ed6c5126bae7f3bb3ccce2ffac4
Previous-Reviewed-on: https://chromium-review.googlesource.com/192610
(cherry picked from commit ab24ba3a112c463a946c02eba2d8620a27197371)
Reviewed-on: https://chromium-review.googlesource.com/192883
Reviewed-by: Yu-Ju Hong <yjhong@chromium.org>
Tested-by: Yu-Ju Hong <yjhong@chromium.org>
1 file changed