check if values are properties of passes object

it seems that mysql 2.0.0-alpha3 adds functions to the result sets which were added to the dao instances and broke the specs. the check makes sure, that only the actual values are added to the dao instance

lib/dao.js

@@ -259,12 +259,12 @@ module.exports = (function() {
   // private
 
   var initAttributes = function(values) {
-    var self = this
-
     // add all passed values to the dao and store the attribute names in this.attributes
     for (var key in values) {
+      if (values.hasOwnProperty(key)) {
         this.addAttribute(key, values[key])
       }
+    }
 
     // set id to null if not passed as value
     // a newly created dao has no id