Bug 17028: Fix XSS in reserve/request.pl

Bug 17028: Fix XSS in reserve/request.pl

Test plan:
Hit
  /cgi-bin/koha/reserve/request.pl?biblionumber=1"><script type="text/javascript">alert("XSS")</script>

=> Without this patch you will see the alert
=> With this patch, no more alert

Signed-off-by: Chris Cormack <chris@bigballofwax.co.nz>
Signed-off-by: Katrin Fischer <katrin.fischer.83@web.de>
Signed-off-by: Brendan Gallagher <brendan@bywatersolutions.com>
(cherry picked from commit 66f81fc2101f194d39592bc28f3e2ff69764bc00)
Signed-off-by: Frédéric Demians <f.demians@tamil.fr>