Bug 18649: Translatability: Get rid of tt directive in translation for admin/categori...

Bug 18649: Translatability: Get rid of tt directive in translation for admin/categories.tt and onboardingstep2.tt

New patch without trailing IF construction in tt directives as
requested in comment #28

To test: Verify that translation tool no longer shows tt directives as
described in comment #1

New patch, needs SO.

Signed-off-by: Owen Leonard <oleonard@myacpl.org>
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 79338bde3e01708fe331a54745f45c620c121805)
Signed-off-by: Fridolin Somers <fridolin.somers@biblibre.com>