Bug 8201: Receive date not passed through correctly

Bug 8201: Receive date not passed through correctly

All orders were received with today's date instead of the receive date
given with the invoice number.

To test:
1) Add an order with a few order lines
2) Create a new invoice, receive date != today's date
3) Start receiving orders, check date on receive screens is correct

Signed-off-by: Matthias Meusburger <matthias.meusburger@biblibre.com>
Signed-off-by: MJ Ray <mjr@phonecoop.coop>
Signed-off-by: Paul Poulain <paul.poulain@biblibre.com>
Signed-off-by: Chris Cormack <chrisc@catalyst.net.nz>