Attempt connection to local webdriver then lab

Now that we have a webdriver server running in the lab at all times
if we cannot establish a connection to a local version switch to
using the lab service.

TEST=Manual; ran it
BUG=None

Change-Id: Ibc77e5cccaf85812b0d4979ed09634c67713252f
Reviewed-on: https://gerrit.chromium.org/gerrit/56661
Tested-by: Kris Rambish <krisr@chromium.org>
Reviewed-by: Tan Gao <tgao@chromium.org>
Reviewed-by: Kris Rambish <krisr@chromium.org>
Commit-Queue: Kris Rambish <krisr@chromium.org>
2 files changed