Add hook_update_last_removed() for consistent schemas

It looks like this module expects at least update 7003 to have run, because it requires the newer database structure with a field_name_revision_id column in the field data table for field collections.

Based on the dates of some code changes... I think we should probably just stick with the Backdrop recommendation of fully upgrading a module from Drupal before migrating to Backdrop... and add 7009 as the "last removed".