refactored pg lib usage

lib/dialects/postgres/connector-manager.js

 var Query   = require("./query")
   , Utils   = require("../../utils")
-  , pg  = require("pg")
-  , without = function(arr, elem) { return arr.filter(function(e) { return e != elem }) }
 
 module.exports = (function() {
   var ConnectorManager = function(sequelize, config) {
     this.sequelize = sequelize
-    this.client = null
-    this.config = config || {}
-    this.pooling = (this.config.poolCfg != null && this.config.poolCfg.maxConnections > 0)
-    if (this.config.native) {
-      pg = pg.native
-    }
+    this.client    = null
+    this.config    = config || {}
+    this.pooling   = (!!this.config.poolCfg && (this.config.poolCfg.maxConnections > 0))
+    this.pg        = this.config.native ? require('pg').native : require('pg')
+
     // set pooling parameters if specified
     if (this.pooling) {
-      pg.defaults.poolSize = this.config.poolCfg.maxConnections
-      pg.defaults.poolIdleTimeout = this.config.poolCfg.maxIdleTime
+      this.pg.defaults.poolSize        = this.config.poolCfg.maxConnections
+      this.pg.defaults.poolIdleTimeout = this.config.poolCfg.maxIdleTime
     }
+
     this.disconnectTimeoutId = null
     this.pendingQueries = 0
     this.maxConcurrentQueries = (this.config.maxConcurrentQueries || 50)
@@ -71,11 +69,10 @@ module.exports = (function() {
 
     if (this.pooling) {
       // acquire client from pool
-      pg.connect(uri, connectCallback)
-
+      this.pg.connect(uri, connectCallback)
     } else {
       //create one-off client
-      this.client = new pg.Client(uri)
+      this.client = new this.pg.Client(uri)
       this.client.connect(connectCallback)
     }
   }