Bug 29111: Remove unused indicator modification code for items

Bug 29111: Remove unused indicator modification code for items

The indicator value for 952 was hard coded in every case to " ". In
order to achieve that we can simply pass undef to TransformHtmlToXml()
and it will set the indicator values to " ".

To test:
 1) Make sure the submission of (at least some) the modified files
 still work, e.g. test that making a new item via
 cataloguing/additem.pl works.

Signed-off-by: Petro Vashchuk <stalkernoid@gmail.com>
Signed-off-by: Katrin Fischer <katrin.fischer.83@web.de>
Rebased-by: Joonas Kylmälä <joonas.kylmala@iki.fi>
Signed-off-by: Jonathan Druart <jonathan.druart@bugs.koha-community.org>