Bug 9280: FIX price calculation adding an order from a staged file

Bug 9280: FIX price calculation adding an order from a staged file

Test plan:
Add an order from a staged file containing a price value (010$d for
UNIMARC user).
Check this patch with 2 different vendors (listprice=1 and listprice=0).
Check the calculated price (depending discount and gstrate).

Signed-off-by: mathieu saby <mathieu.saby@univ-rennes2.fr>
Signed-off-by: Elliott Davis <elliott@bywatersolions.com>
introduces no new bugs
Signed-off-by: Jared Camins-Esakov <jcamins@cpbibliography.com>
I was unable to replicate the bug in MARC21, but the patch introduces
no regressions that I could find, so I am pushing it anyway.
Note: Acquisitions remains unusable under Plack. In order to test this
patch I first applied the patch on bug 9432.