Move chromeos-factory into mod_image_for_test

Previously it was a dependency of chromeos-test which isn't correct

BUG=none
TEST=Build base and factory images

Change-Id: I133b937d1b56f96d5ebf3428172f9a4457c6bf5e
Reviewed-on: https://gerrit.chromium.org/gerrit/31156
Reviewed-by: Richard Barnette <jrbarnette@chromium.org>
Commit-Ready: Liam McLoughlin <lmcloughlin@chromium.org>
Tested-by: Liam McLoughlin <lmcloughlin@chromium.org>
2 files changed