Bug 21587: don't drop patrons to notify in order creation

Bug 21587: don't drop patrons to notify in order creation

It only worked on modification.

== Test plan ==
1. have/create a active budget
2. have/create a fund
3. have/create a vendor with minimal info
4. create a basket with minimal info
5. add an order line to the basket
     Add a user in "To notify on receiving"
6. Modify the order
7. The patrons isn't here. This is the bug
8. Add a user in "To notify on receiving"
9. Save
10. Modify the order
11. The patron is here now
12. Apply this patch
13. Retry step 5 to 11 and patron should be saved on order creation
14. Celebrate! :D

Signed-off-by: Jonathan Druart <jonathan.druart@bugs.koha-community.org>
Signed-off-by: Katrin Fischer <katrin.fischer.83@web.de>
Signed-off-by: Nick Clemens <nick@bywatersolutions.com>