[luci-config] log more
[luci-config] log more

Add logging to diagnose crbug.com/819453

R=a30c74fa30536fe7ea81ed6dec202e35e149e1fd@chromium.org

Bug: 819453
Change-Id: I547f539f4ddef9b4abfe1d6b81dd99be0cc9afbb
Reviewed-on: https://chromium-review.googlesource.com/967371
Reviewed-by: Andrii Shyshkalov <a30c74fa30536fe7ea81ed6dec202e35e149e1fd@chromium.org>
Commit-Queue: Nodir Turakulov <ef4933a197ef7b4b3f55f1bec4942aead3637a2a@chromium.org>

luci/luci-py,luci/luci-py,luci/luci-py,luci/luci-py