ES6 refactor of promise.js (#6081)

let, const, arrow functions, export default

lib/promise.js

 'use strict';
 
-var Promise = require('bluebird')
-  , shimmer = require('shimmer');
+const Promise = require('bluebird');
+const shimmer = require('shimmer');
 
 // functionName: The Promise function that should be shimmed
 // fnArgs: The arguments index that should be CLS enabled (typically all callbacks). Offset from last if negative
 function shimCLS(object, functionName, fnArgs){
-  shimmer.wrap(object, functionName, function(fn) {
+  shimmer.wrap(object, functionName, fn => {
     return function () {
       if (Promise.Sequelize && Promise.Sequelize.cls) {
-        var ns = Promise.Sequelize.cls;
-        for(var x=0; x<fnArgs.length; x++) {
-          var argIndex = fnArgs[x] < 0 ? arguments.length + fnArgs[x] : fnArgs[x];
+        const ns = Promise.Sequelize.cls;
+        for(let x = 0; x < fnArgs.length; x++) {
+          const argIndex = fnArgs[x] < 0 ? arguments.length + fnArgs[x] : fnArgs[x];
           if ( argIndex < arguments.length && typeof arguments[argIndex] === 'function' ) {
             arguments[argIndex] = ns.bind( arguments[argIndex] );
           }
@@ -51,3 +51,5 @@ shimCLS(Promise.prototype, 'tap', [0]);
 shimCLS(Promise.prototype, 'done', [0, 1]);
 
 module.exports = Promise;
+module.exports.Promise = Promise;
+module.exports.default = Promise;