Invoke skull-and-crossbones popup in batch receive for server-side errors

And introduce a minor bumper rail to guide serials users who might try
to hand-edit a holding code.

Signed-off-by: Lebbeous Fogle-Weekley <lebbeous@esilibrary.com>

Conflicts:
    Open-ILS/xul/staff_client/server/serial/batch_receive.js

Signed-off-by: Dan Wells <dbw2@calvin.edu>