Fixed input name selector in csrf form update

src/rails.js

@@ -378,7 +378,7 @@
     // making sure that all forms have actual up-to-date token(cached forms contain old one)
     csrf_token = $('meta[name=csrf-token]').attr('content');
     csrf_param = $('meta[name=csrf-param]').attr('content');
-    $('form input[name='+csrf_param+']').val(csrf_token);
+    $('form input[name="' + csrf_param + '"]').val(csrf_token);
   });
 
 })( jQuery );