Merge branch 'jt/de-global-bulk-checkin'

The bulk-checkin code used to depend on a file-scope static singleton variable, which has been updated to pass an instance throughout the callchain. * jt/de-global-bulk-checkin: bulk-checkin: use repository variable from transaction bulk-checkin: require transaction for index_blob_bulk_checkin() bulk-checkin: remove global transaction state bulk-checkin: introduce object database transaction structure