Bug 21554: Add missing use statement in subscription-batchedit

Signed-off-by: Mark Tompsett <mtompset@hotmail.com>
Signed-off-by: Julian Maurice <julian.maurice@biblibre.com>

Signed-off-by: Nick Clemens <nick@bywatersolutions.com>

serials/subscription-batchedit.pl

@@ -23,6 +23,7 @@ use CGI qw( -utf8 );
 
 use C4::Auth;
 use C4::Output;
+use C4::Serials;
 use Koha::Subscriptions;
 use Koha::Acquisition::Booksellers;
 use Koha::AdditionalField;