Backport PR #6736

---------

**Commit 1:**
[internal] Remove all variable redeclarations

Redeclaring variables causes ambiguity and serves no purpose. It
actually causes a runtime error when you do it with `let`, and we can
enforce not doing it via a linter rule.

* Original sha: de20762
* Authored by Court Ewing <court@epixa.com> on 2016-04-01T18:21:55Z

src/ui/public/agg_types/buckets/range.js

@@ -26,7 +26,7 @@ define(function (require) {
 
         var id = RangeKey.idBucket(bucket);
 
-        var key = keys.get(id);
+        key = keys.get(id);
         if (!key) {
           key = new RangeKey(bucket);
           keys.set(id, key);

test/fixtures/scenario_manager.js

@@ -120,7 +120,6 @@ ScenarioManager.prototype.loadIfEmpty = function (id) {
   var scenario = config[id];
   if (!scenario) throw new Error('No scenario found for ' + id);
 
-  var self = this;
   return Promise.all(scenario.bulk.map(function mapBulk(bulk) {
     var loadIndexDefinition;
 

test/functional/apps/discover/index.js

@@ -9,7 +9,6 @@ define(function (require) {
   var collapseExpand = require('./_collapse_expand');
 
   bdd.describe('discover app', function () {
-    var scenarioManager;
     var remote;
     var scenarioManager = new ScenarioManager(url.format(config.servers.elasticsearch));
     this.timeout = config.timeouts.default;

test/functional/apps/visualize/index.js

@@ -20,7 +20,6 @@ define(function (require) {
 
   bdd.describe('visualize app', function () {
     var common;
-    var scenarioManager;
     var remote;
     var headerPage;
     var settingsPage;