Bug 30524: (QA follow-up) Only generate CSRF token if it will be used

Bug 30524: (QA follow-up) Only generate CSRF token if it will be used

This patch avoids generating CSRF tokens unless the csrf-token.inc file
is included in the template.

Passed token doesn't need HTML escaped. The docs for WWW::CSRF state:
  The returned CSRF token is in a text-only form suitable for inserting into a HTML form without further escaping (assuming you did not send in strange things to the Time option).

Signed-off-by: Tomas Cohen Arazi <tomascohen@theke.io>
(cherry picked from commit ddf1eb6cef14da365675890920ff72f010c59527)
Signed-off-by: Fridolin Somers <fridolin.somers@biblibre.com>