[autotest] Add in the helper url to gs_offloader eMail.

go/cros-triage-gsoffloader contains more helpful info
with regards to triaging issues with gs_offloader.

BUG=chromium:529494
TEST=Ran gs_offloader unittests

Change-Id: I66890d130b1e16c986bdc20de711de021e89c69d
Reviewed-on: https://chromium-review.googlesource.com/298066
Commit-Ready: Kevin Cheng <kevcheng@google.com>
Tested-by: Kevin Cheng <kevcheng@google.com>
Reviewed-by: Richard Barnette <jrbarnette@chromium.org>
2 files changed