fix bug: Using options in aggregates doesn't set anything

Author: spederiva

lib/aggregate.js

@@ -564,7 +564,7 @@ Aggregate.prototype.allowDiskUse = function(value) {
  */
 
 Aggregate.prototype.option = function(value) {
-  for (var key in Object.keys(value)) {
+  for (var key in value) {
     this.options[key] = value[key];
   }
   return this;