Bug 16587 opac-sendshelf.pl is vulnerable to XSS

Bug 16587 opac-sendshelf.pl is vulnerable to XSS

To test
1/ Hit a url like
http://localhost:8080/cgi-bin/koha/opac-sendshelf.pl?email=%3Cscript%3Ealert(%27XSS%27)%3C%2Fscript%3Ezz%40zz&comment=tes&shelfid=4
2/ Notice you get a js alert
3/ Apply patch
4/ Notice the js is now escaped

Signed-off-by: Jonathan Druart <jonathan.druart@bugs.koha-community.org>
Signed-off-by: Kyle M Hall <kyle@bywatersolutions.com>
Signed-off-by: Brendan Gallagher <brendan@bywatersolutions.com>
(cherry picked from commit 4e817ee04c2b5fbc2353ff382c6630322e57d8ae)
Signed-off-by: Julian Maurice <julian.maurice@biblibre.com>