Bug 19582: Use compat routines for searching authorities in auth_finder.pl

Bug 19582: Use compat routines for searching authorities in auth_finder.pl

To test:
1 - Enable Zebra
2 - Perform an auth search
3 - note results
4 - Enable ES
5 - Repeat search, note (likely) diff results
6 - Open a record in cataloging and use the button to launch auth search
7 - Perform same search as above, note results match for eiher engine
selected
8 - NOTE: Disbale sorting for ES search - this will be dealt with in
another report

Signed-off-by: David Bourgault <david.bourgault@inlibro.com>
Signed-off-by: Nicolas Legrand <nicolas.legrand@bulac.fr>
Signed-off-by: Alex Arnaud <alex.arnaud@biblibre.com>
Signed-off-by: Jonathan Druart <jonathan.druart@bugs.koha-community.org>