Bug 18996: Resolve an uninitialized warning from ILS/Item.pm

Bug 18996: Resolve an uninitialized warning from ILS/Item.pm

From the syslog call on line 107/108. The field $item->{title} has not
been initialized. When catching the warns in a test script with Test::Warn,
I got:
    Use of uninitialized value $args[1] in sprintf at /usr/lib/x86_64-linux-gnu/perl/5.20/Sys/Syslog.pm line 423.

This simply resolves the warning. We might have a closer look to this title
field on another report though.

Test plan:
Run Message.t from the next patch without this fix. It will fail since the
additional warning makes warnings_like return false.

Signed-off-by: Marcel de Rooy <m.de.rooy@rijksmuseum.nl>
Signed-off-by: Colin Campbell <colin.campbell@ptfs-europe.com>
Signed-off-by: Kyle M Hall <kyle@bywatersolutions.com>
Signed-off-by: Jonathan Druart <jonathan.druart@bugs.koha-community.org>