[autotest] Add logging of state 'locked' for model_logic

This will help us to determine whether abnormalities in statuses such as
repair failed are actual problems. If a host is locked, we typically
don't care about its status when doing analysis. I looked at rpc_interface.py,
seems like there are two calls modify_hosts and modify_host that call
update_object(host) only after checking for invalid modifications. So I
decided to log the data in rpc_interface.py

BUG=chromium:394451
TEST=On local afe added a host and via frontend locked and unlocked host.
     Verified results in es db.

Change-Id: I0362f64d0c8270dc9373a421944e024ef0175ecd
Reviewed-on: https://chromium-review.googlesource.com/209268
Tested-by: Michael Liang <michaelliang@chromium.org>
Reviewed-by: Dan Shi <dshi@chromium.org>
Commit-Queue: Michael Liang <michaelliang@chromium.org>
1 file changed