When an item is recalled, Koha looks to the relevant due date interval circulation rule to adjust the checkout's due date. If the circulation rule for recall due date interval is not defined (empty), Koha defaults to 5 days. We should remove this default so that if the circulation rule for recall due date interval is left empty, then the checkout due date is not adjusted. This has been prompted by a library who uses recalls in a way that the due date is not adjusted, but the patron is charged a specific recall fine if they are late to return it.