CAY-1885 Null value in subclass's field.

release notes

git-svn-id: https://svn.apache.org/repos/asf/cayenne/main/branches/STABLE-3.1@1553818 13f79535-47bb-0310-9956-ffa450edef68
fixing items order

git-svn-id: https://svn.apache.org/repos/asf/cayenne/main/branches/STABLE-3.1@1553819 13f79535-47bb-0310-9956-ffa450edef68