[autotest] thread --ssh_options parameter through test_that

BUG=chromium:285378
TEST=Unit tests pass. Manually verified that parameter threads to
autoserv.

Change-Id: Ib19fe8c378ae71f5c5432f82f919fd761a10ca80
Reviewed-on: https://chromium-review.googlesource.com/168072
Reviewed-by: Aviv Keshet <akeshet@chromium.org>
Tested-by: Aviv Keshet <akeshet@chromium.org>
Commit-Queue: Aviv Keshet <akeshet@chromium.org>
2 files changed