Deprecate factory related scripts.

With recent changes the factory build process is now all done in package
"emerge chromeos-factory". We don't need further post-processing by
calling make_factory_toolkit.

make_factory_package and serve_factory_package should always run from
factory/setup (or from the factory.zip), especially now we are migrating
to Umpire server. It should be safe to remove these symlink and
deprecated commands now.

BUG=chromium:577601
TEST=./make_factory_toolkit.sh

Change-Id: I872973f7bf9aa24eb5fb432148014d6b02f775a6
Reviewed-on: https://chromium-review.googlesource.com/397084
Commit-Ready: Hung-Te Lin <hungte@chromium.org>
Tested-by: Hung-Te Lin <hungte@chromium.org>
Reviewed-by: Ting Shen <phoenixshen@chromium.org>
3 files changed