Fixed bug introduced in rev 1490678 (removal of cached DOM tree code and refactoring for thread-safety): after that commit it was not possible to define entity data readers at runtime, this fix re-enables the feature.

git-svn-id: https://svn.apache.org/repos/asf/ofbiz/trunk@1516094 13f79535-47bb-0310-9956-ffa450edef68