Bug 19746: Remove debug statements in returns.pl

Bug 19746: Remove debug statements in returns.pl

From bug commit bb6277ffcc593685554112d770ac273c9efeda33
Bug 14464: Add ability to cancel waiting holds from checkin screen

+use Carp 'verbose';
+$SIG{ __DIE__ } = sub { Carp::confess( @_ ) };

See also
http://lists.koha-community.org/pipermail/koha-devel/2017-November/044168.html

Test plan:
Read the changes and make sure they make sense

Signed-off-by: Tomas Cohen Arazi <tomascohen@theke.io>
Signed-off-by: Julian Maurice <julian.maurice@biblibre.com>
Signed-off-by: Jonathan Druart <jonathan.druart@bugs.koha-community.org>