Fix the ref to dataSource

lib/datasource.js

@@ -132,6 +132,7 @@ DataSource.prototype._setupConnector = function () {
             // Set up the dataSource if the connector doesn't do so
             this.connector.dataSource = this;
         }
+        var dataSource = this;
         this.connector.log = function (query, start) {
             dataSource.log(query, start);
         };