common.sh: deprecate .chromeos_dev

This file has been around since the start of the project, but it's
never been documented.  It's also a bit dicey -- it loads itself in
the middle of all our build scripts.  It's intended to set some vars
to default values, but the loose convention no longer really holds
(only set vars that start with CHROMEOS_, but we don't have those
anymore).  It's also not been supported as we migrated code over to
chromite/python and no one has complained.

Mark it as deprecated so any devs using it will let us know.

BUG=None
TEST=CQ passed

Change-Id: Id87d7fac4ad804a10147aa802a933c16df372a1b
Reviewed-on: https://chromium-review.googlesource.com/1764953
Tested-by: Mike Frysinger <vapier@chromium.org>
Commit-Ready: Mike Frysinger <vapier@chromium.org>
Legacy-Commit-Queue: Commit Bot <commit-bot@chromium.org>
Reviewed-by: Alex Klein <saklein@chromium.org>
2 files changed