Bug 29789: Remove unused $error from cataloguing/additem.pl

Bug 29789: Remove unused $error from cataloguing/additem.pl

my $error        = $input->param('error');

It should be removed as $error is used later but not related to this variable.

Signed-off-by: Tomas Cohen Arazi <tomascohen@theke.io>
Signed-off-by: Kyle M Hall <kyle@bywatersolutions.com>
Signed-off-by: Fridolin Somers <fridolin.somers@biblibre.com>
Signed-off-by: Kyle M Hall <kyle@bywatersolutions.com>
(cherry picked from commit b85e3cb81181529698e39219fe5ccc9b62c7e243)

Signed-off-by: Andrew Fuerste-Henry <andrew@bywatersolutions.com>