Bug 17411 - Change exit 1 to exit 0 in acqui/basket.pl to prevent Internal Server Error

Note: Same situation as in Bug 17403

To test:
- Verifiy that code change makes sense.

Note: Same situation as in Bug 17403
Signed-off-by: David Cook <dcook@prosentient.com.au>

Signed-off-by: Jonathan Druart <jonathan.druart@bugs.koha-community.org>
Amended patch: Remove unecessary comment

Signed-off-by: Kyle M Hall <kyle@bywatersolutions.com>
(cherry picked from commit 01636dca2f)
Signed-off-by: Frédéric Demians <f.demians@tamil.fr>
(cherry picked from commit f388905913)
Signed-off-by: Julian Maurice <julian.maurice@biblibre.com>

acqui/basket.pl

@@ -223,7 +223,7 @@ if ( $op eq 'delete_confirm' ) {
               || ( $basket->{branch}  eq '' );
             unless ($validtest) {
                 print $query->redirect("../mainpage.pl");
-                exit 1;
+                exit 0;
             }
         }
         if (!defined $basket->{branch} or $basket->{branch} eq $userenv->{branch}) {