Bug 14521: SQL injection in local use system preferences

Bug 14521: SQL injection in local use system preferences

This patch fixes a SQL injection vulnerability in the local use
system preferences.

_TEST PLAN_

Before applying:

1) Go to Global System Preferences
2) Click on the "Local use" tab
3) Add a new preference with the value "') or '1' = '1' -- "
(be sure to include the space at the end after the comment --).
4) When the page refreshes, you should now see about 99 other system
preferences which shouldn't be showing up.

5) Apply the patch

6) Refresh the page
7) Note that you now only see a system preference for "') or '1' = '1' -- "
and the other actual local use system preferences.

Signed-off-by: Chris Cormack <chrisc@catalyst.net.nz>
Signed-off-by: Jonathan Druart <jonathan.druart@bugs.koha-community.org>
Signed-off-by: Tomas Cohen Arazi <tomascohen@unc.edu.ar>