Bug 15083: Remove acqui/currency.pl

Bug 15083: Remove acqui/currency.pl

This script has scary FIXMEs and can be removed.
It is never called from Koha code.
On the way, this patch remove the C4::Budgets::ModCurrencies subroutine,
which was only called from this script.

Test plan:
  git grep 'acqui/currency.pl
and
  git grep ModCurrencies
should not return anything.

Signed-off-by: Bernardo Gonzalez Kriegel <bgkriegel@gmail.com>
No more ModeCurrencies, no call to acqui/currency.pl
No errors

Signed-off-by: Katrin Fischer <katrin.fischer.83@web.de>
Signed-off-by: Tomas Cohen Arazi <tomascohen@theke.io>