A patch from Leon for "correction to changeset r1626462  and r1626463  " https://issues.apache.org/jira/browse/OFBIZ-5869

Uses now timestamp to replace "null" value.

git-svn-id: https://svn.apache.org/repos/asf/ofbiz/trunk@1645950 13f79535-47bb-0310-9956-ffa450edef68