Bug 28768: remove unnessesary template variable

Bug 28768: remove unnessesary template variable

To test:
1. Add some news that should display on opac-readingrecord.pl. For example: opacheader, OpacCustomSearch, opaccredits
2. Go to opac-readingrecord.pl, the news doesn't display
3. Apply patch, restart_all
4. Go to opac-readingrecord.pl, the news displays
5. Turn on 'opacreadinghistory' and test to make sure it still works

Signed-off-by: Andrew Isherwood <andrew.isherwood@ptfs-europe.com>
Signed-off-by: Nick Clemens <nick@bywatersolutions.com>
Signed-off-by: Jonathan Druart <jonathan.druart@bugs.koha-community.org>