Serials receiving: duplicate barcode should display explicit error

EG 3-9-1

When receiving a serial issuance, the user has the option to create an item. If the user enters a duplicate barcode for the item, the action fails displaying the message: "Failed to save issuance." This message is not useful Instead,there should be an explicit error message indicating why the action failed.

Workflow:

--Select a serial title in the catalog
--Select "Manage Subscriptions" from the "Serials" button
--Select the "Manage Issues" tab
--Choose an expected issuance
--Choose "Receive selected" from the Actions menu; note: be sure you have selected the option to "Barcode on receive"
--Select the correct shelving location and circulation modifier; enter the call number and a barcode that you know is a duplicate
--Observe that the system displays the message "Failed to save issuance."