Bug 18689: calendar error with double quotes in title or description of holiday

Bug 18689: calendar error with double quotes in title or description of holiday

This patch fixes the calendar display with holidays having double qoutes in
title or description.

To test:
- Apply patch
- Go to Home > Tools > Calendar
- Create new holidays of each type (Day only, repeated wekly/yearly,
  range, yearly repeated range and enter double qoutes in their titles and
  descriptions
- Verify that calendar displays and works as expected
- Verify that you can edit the holidays

Signed-off-by: Lee Jamison <ldjamison@marywood.edu>
Signed-off-by: Jonathan Druart <jonathan.druart@bugs.koha-community.org>