[buildbucket] Fix printing build url
[buildbucket] Fix printing build url

TBR=smut@chromium.org,nodir@chromium.org

Bug: 711249
Change-Id: I031497eeeec02f16c182fbe2e46c6a02f0745df9
Reviewed-on: https://chromium-review.googlesource.com/1232896
Reviewed-by: Michael Achenbach <76cc7f10de6bc994d83c4cb09072e4590b82b709@chromium.org>
Commit-Queue: Michael Achenbach <76cc7f10de6bc994d83c4cb09072e4590b82b709@chromium.org>

CoherentLabs/depot_tools,CoherentLabs/depot_tools