remove bind polyfill from u2f/register.js

app/assets/javascripts/u2f/register.js

@@ -8,19 +8,17 @@
 // State Flow #1: setup -> in_progress -> registered -> POST to server
 // State Flow #2: setup -> in_progress -> error -> setup
 (function() {
-  var bind = function(fn, me) { return function() { return fn.apply(me, arguments); }; };
-
   this.U2FRegister = (function() {
     function U2FRegister(container, u2fParams) {
       this.container = container;
-      this.renderNotSupported = bind(this.renderNotSupported, this);
-      this.renderRegistered = bind(this.renderRegistered, this);
-      this.renderError = bind(this.renderError, this);
-      this.renderInProgress = bind(this.renderInProgress, this);
-      this.renderSetup = bind(this.renderSetup, this);
-      this.renderTemplate = bind(this.renderTemplate, this);
-      this.register = bind(this.register, this);
-      this.start = bind(this.start, this);
+      this.renderNotSupported = this.renderNotSupported.bind(this);
+      this.renderRegistered = this.renderRegistered.bind(this);
+      this.renderError = this.renderError.bind(this);
+      this.renderInProgress = this.renderInProgress.bind(this);
+      this.renderSetup = this.renderSetup.bind(this);
+      this.renderTemplate = this.renderTemplate.bind(this);
+      this.register = this.register.bind(this);
+      this.start = this.start.bind(this);
       this.appId = u2fParams.app_id;
       this.registerRequests = u2fParams.register_requests;
       this.signRequests = u2fParams.sign_requests;