DEICH-5580 consider c/o location on checkin

Unfortunately, we haven't completed the transition to using item location lives|goes|co, but still is left with a mix of old logic (read: branchtransfers) and partly implemented location logic.

This change makes checkin consider the branch of c/o location if present, and complete branchtransfer if the branch is the same as the branch where the checkin is performed, disregarding the branchtransfer.tobranch.

Closes DEICH-5580