Remove use of deprecated 'modulemessages'

Deprecated as of MediaWiki 1.26, replaced with an empty array.

Change-Id: Ic5f308060f796b896f98de34e153bb8bd11f8e6c

modules/jquery.wikiEditor.preview.js

@@ -76,8 +76,7 @@ fn: {
 
 					var loadmodules = data.parse.modules.concat(
 						data.parse.modulescripts,
-						data.parse.modulestyles,
-						data.parse.modulemessages
+						data.parse.modulestyles
 					);
 					mw.loader.load( loadmodules );
 				} );