Fix reducedObject when default property is undefined

lib/utils/reducedObject.js

@@ -4,8 +4,13 @@ var Immutable = require('immutable');
  *  Reduce the difference between a map and its default version
  *  @param {Map} defaultVersion
  *  @param {Map} currentVersion
+ *  @return {Map} The properties of currentVersion that differs from defaultVersion
  */
 function reducedObject(defaultVersion, currentVersion) {
+    if(defaultVersion === undefined) {
+        return currentVersion;
+    }
+
     return currentVersion.reduce(function(result, value, key) {
         var defaultValue = defaultVersion.get(key);