Bug 23658: fix wrong transfer modal dropping specified checkin date

Bug 23658: fix wrong transfer modal dropping specified checkin date

To test:

Have an item that needs a transfer
use the check in page, and backdate the checkin date
check in the item, click ok or print - backdating is OK
Check it in again - backdating drops off
Apply this patch, restart the things
run tests again, backdating should be retained in all cases.

Signed-off-by: Katrin Fischer <katrin.fischer.83@web.de>
Signed-off-by: Martin Renvoize <martin.renvoize@ptfs-europe.com>
Signed-off-by: Lucas Gass <lucas@bywatersolutions.com>