Bug 18633: Remove useless use of CGI TT plugin

Bug 18633: Remove useless use of CGI TT plugin

The form is sent using AJAX so there is never a query string in
the URL (no POST parameters either)

Tested both patches together, item search behaves as before, log
entries are gone
Signed-off-by: Marc Véron <veron@veron.ch>
Signed-off-by: Marcel de Rooy <m.de.rooy@rijksmuseum.nl>
Signed-off-by: Jonathan Druart <jonathan.druart@bugs.koha-community.org>
(cherry picked from commit a000d95a4d322607eccdbf08abc94dd78d4e5617)
Signed-off-by: Fridolin Somers <fridolin.somers@biblibre.com>