Incorporate chromiumos_host.py into site_host.py

This change is separate from the previous change to simplify
reviewing the change in Gerrit.

BUG=chromium-os:29209
TEST=run BVT

Change-Id: I6113469fa2dc6dfecfd2c7fa748649e15e673410
Reviewed-on: https://gerrit.chromium.org/gerrit/20034
Tested-by: Richard Barnette <jrbarnette@chromium.org>
Reviewed-by: Chris Masone <cmasone@chromium.org>
Commit-Ready: Richard Barnette <jrbarnette@chromium.org>
2 files changed