add stub for local_id_for

Change-Id: I6d462ffb86a20ed197795c96437b5e281ae8fedf
Reviewed-on: https://gerrit.instructure.com/31793
Tested-by: Jenkins <jenkins@instructure.com>
Reviewed-by: Cody Cutrer <cody@instructure.com>
Product-Review: Rob Orton <rob@instructure.com>
QA-Review: Rob Orton <rob@instructure.com>