removed duplicated comparison

lib/associations/has-many-double-linked.js

@@ -26,7 +26,7 @@ module.exports = (function() {
           options.where[self.__factory.target.tableName+"."+index] = value;
         });
 
-        options.where = options.where ? Utils._.extend(options.where, where) : where
+        Utils._.extend(options.where, where)
       } else {
         options.where = where;
       }