RJournal.layout: remove unneeded code

Part of this code was moved to the template in a previous commit
and part was removed because it is no longer needed.

Patch by Yihui Xie.

lib/layouts/RJournal.layout

@@ -18,13 +18,6 @@ AddToPreamble
 	\bibliographystyle{abbrvnat}
 	\usepackage{booktabs}
 
-	% use Schunk, Sinput and Soutput environments defined by RJournal
-	<<include=FALSE>>=
-	render_sweave()
-	set_header(highlight = '')
-	knit_hooks$set(document = hook_rjournal)
-	@
-
 	\fancyhf{}
 	\fancyhead[LO,RE]{\textsc{Contributed Article}}
 	\fancyhead[RO,LE]{\thepage}