[autotest] Include links to failed test logs in suite output

When tests driven by the buildbot fail, we want to provide
some way for sheriffs to check out the logs.
Emit annotated log links for buildbot to consume and print
inline in the waterfall.

BUG=chromium-os:26857
TEST=./site_utils/run_suite.py -b x86-mario -i x86-mario-release/R19-1865.0.0-a1-b1702 -s dummy
TEST=The output from the above command should have several @@@STEP_LINK lines.

Change-Id: Ie73b3393fab328cb9f0ed8c4dcdf5926968f1e74
Reviewed-on: https://gerrit.chromium.org/gerrit/17090
Tested-by: Chris Masone <cmasone@chromium.org>
Reviewed-by: Chris Sosa <sosa@chromium.org>
Commit-Ready: Chris Masone <cmasone@chromium.org>
2 files changed