check for turbolinks classic before teardown

Author: glosie

react_ujs/src/events/detect.js

@@ -9,7 +9,9 @@ var turbolinksClassicEvents = require("./turbolinksClassic")
 module.exports = function(ujs) {
   if (ujs.handleEvent) {
     // We're calling this a second time -- remove previous handlers
-    turbolinksClassicEvents.teardown(ujs)
+    if (typeof Turbolinks.EVENTS !== "undefined") {
+      turbolinksClassicEvents.teardown(ujs);
+    }
     turbolinksEvents.teardown(ujs);
     turbolinksClassicDeprecatedEvents.teardown(ujs);
     pjaxEvents.teardown(ujs);