Bug 19086: Fix Stored XSS in circulation.pl

Bug 19086: Fix Stored XSS in circulation.pl

1/ To test add a message to a borrower that contains js
2/ hit /cgi-bin/koha/circ/circulation.pl?borrowernumber=[number]
  where number is the borrowernumber of the borrower you set the message
  for
3/ Notice js is execute
4/ Apply patch, reload, js is escaped

Signed-off-by: Amit Gupta <amit.gupta@informaticsglobal.com>
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>