warning message when mysql dialect is loaded without mysql module installed

lib/dialects/mysql/connector-manager.js

-var mysql   = require("mysql")
+var mysql
   , Pooling = require('generic-pool')
   , Query   = require("./query")
   , Utils   = require("../../utils")
   , without = function(arr, elem) { return arr.filter(function(e) { return e != elem }) }
 
+try { mysql = require("mysql") } catch (err) {
+  console.log("You need to install mysql package manually"); }
+
 module.exports = (function() {
   var ConnectorManager = function(sequelize, config) {
     this.sequelize = sequelize