Bug 7843: Remove the useless use of casAuthentication

Certainly a c/p error from opac-main.pl

Signed-off-by: Pierre <tredok.pierre@gmail.com>
Signed-off-by: Kyle M Hall <kyle@bywatersolutions.com>
Signed-off-by: Tomas Cohen Arazi <tomascohen@gmail.com>

opac/opac-news-rss.pl

@@ -42,11 +42,6 @@
     }
 );
 
-my $casAuthentication = C4::Context->preference('casAuthentication');
-$template->param(
-    casAuthentication   => $casAuthentication,
-);
-
 # Get the news to display
 # use cookie setting for language, bug default to syspref if it's not set
 my ($theme, $news_lang, $availablethemes) = C4::Templates::themelanguage(C4::Context->config('opachtdocs'),'opac-main.tt','opac',$input);