Bug 10088: FIX adding an order from a staged file.

Bug 10088: FIX adding an order from a staged file.

Bug 9902 introduced an issue in the C4::Items::PrepareItemrecordDisplay
routine. The existence of $defaulvalue hashref should be tested before
getting to the branchcode key.

Test plan:
Before applying the patch, an error occurred when you try to create an
order from a staged file.
After applying the patch, the error does not appear anymore.

Signed-off-by: Mathieu Saby <mathieu.saby@univ-rennes2.fr>
Signed-off-by: Mason James <mtj@kohaaloha.com>
Signed-off-by: Jared Camins-Esakov <jcamins@cpbibliography.com>