auto-update logic currently is in afe_utils. However, this has some drawbacks:

1. many *_host.py import afe_utils, which make it hard for afe_utils to get any host-related info from importing these *_host.py if it's required by auto-update.

2. other afe_utils' functions focus on utilizing afe to get/update infos, like DUT's board, version and attributes. Put auto_update logic here is not that appropriate.

3. long-term goal is to refactor these complex dependencies between afe/host/devserver for auto-update. It could be regarded as a first step.