Implement functions relative to load config.

There are two ways to load config:
  1. Download from shopfloor server.
  2. Load from a USB drive.

BUG=chrome-os-partner:20996
TEST=make lint & manually tested

Change-Id: I95ddc895ce508e2713629af074c98a9bd154033f
Reviewed-on: https://chromium-review.googlesource.com/171841
Reviewed-by: Dean Liao <deanliao@chromium.org>
Commit-Queue: Mao Huang <littlecvr@chromium.org>
Tested-by: Mao Huang <littlecvr@chromium.org>
2 files changed