Bug 4985: Fix Plack scope errors

Bug 4985: Fix Plack scope errors

This patch 'ours' several variables to fix Plack scope errors
in exceptionHolidays.pl.

This also adds '@holidays_list' as parameter to 'edit_holidays'.

Sponsored-by: Koha-Suomi Oy
Signed-off-by: Sally <sally.healey@cheshiresharedservices.gov.uk>
Signed-off-by: Katrin Fischer <katrin.fischer.83@web.de>
Signed-off-by: Jonathan Druart <jonathan.druart@bugs.koha-community.org>
(cherry picked from commit ee3f5d5a85d93dc36d6bdeab5f092c0098d604e1)

Signed-off-by: Lucas Gass <lucas@bywatersolutions.com>