fix(server/flash): Api to match documentation

This fixes duplication issues and normalize our use with everyone else

server/boot/z-lang-redirect.js

@@ -23,9 +23,7 @@ export default function redirectLang(app) {
     }
 
     if (type === 'html') {
-      req.flash('danger', {
-        msg: `We couldn't find path ${ path }`
-      });
+      req.flash('danger', `We couldn't find path ${ path }`);
       return res.render('404', { title: '404'});
     }