[moblab] Connector class for devserver

Provide a utility class for the scheduler to connect to devserver,
this will eventually be moved into a more generic moblab API
interface and be extended as required.

TEST=unit tests, on local moblabs
BUG=chromium:825013

Change-Id: Ifeac4a2d671b8e17ec606460593ee766c12cf9b7
Reviewed-on: https://chromium-review.googlesource.com/1459903
Commit-Ready: Keith Haddow <haddowk@chromium.org>
Tested-by: Keith Haddow <haddowk@chromium.org>
Reviewed-by: Matt Mallett <mattmallett@chromium.org>
2 files changed