Bug 19108 - Stored XSS in fieldmapping.pl

Bug 19108 - Stored XSS in fieldmapping.pl

To Test
1. Hit the page /cgi-bin/koha/admin/fieldmapping.pl
2. Add a text in the field Field name that contains js
3. Save the page.
4. Notice js is execute
5. Apply patch and reload, the js is escaped

Signed-off-by: Katrin Fischer <katrin.fischer.83@web.de>
Signed-off-by: Marcel de Rooy <m.de.rooy@rijksmuseum.nl>
Signed-off-by: Jonathan Druart <jonathan.druart@bugs.koha-community.org>
(cherry picked from commit 77ddae74d661fb589d74bd85f5561fdd4131af70)
Signed-off-by: Fridolin Somers <fridolin.somers@biblibre.com>