Remove token column from poll_voters table

As it is no longer used as originally pretended [1][2].

[1] Check consul/consul pull request 1994
[2] Check consul/consul pull request 3539

app/assets/javascripts/polls.js

@@ -1,28 +1,7 @@
 (function() {
   "use strict";
   App.Polls = {
-    generateToken: function() {
-      var strings;
-      strings = Array.apply(null, {
-        length: 6
-      }).map(function() {
-        return Math.random().toString(36).substr(2); // remove `0.`
-      });
-      return strings.join("").substring(0, 64);
-    },
-    replaceToken: function(token) {
-      $(".js-question-answer").each(function() {
-        var token_param;
-        token_param = this.search.slice(-6);
-        if (token_param === "token=") {
-          this.href = this.href + token;
-        }
-      });
-    },
     initialize: function() {
-      var token;
-      token = App.Polls.generateToken();
-      App.Polls.replaceToken(token);
       $(".zoom-link").on("click", function(event) {
         var answer;
         answer = $(event.target).closest("div.answer");