Commission Implementing Regulation (EU) Nº 1379/2011 of 20 December 2011 amending Regulations (EC) Nº 382/2008, (EU) Nº 1178/2010 and (EU) Nº 90/2011 as regards the CN codes and the product codes of the agricultural product nomenclature for export refunds in the beef and veal, egg and poultrymeat sectors