CLONE - Fix NPE in journal importer

It was reported that the HornetQ journal importer would throw a NullPointerException (<abbrev>NPE</abbrev>) when passed an argument of <literal>false</literal> for the transactional command line parameter. This was found to be occurring because the XML importer uses two different HornetQ sessions; one for normal send operations and one for management operations. In certain circumstances the management session was not instantiated properly and, when it was used, the NPE was thrown. The XML importer has been updated and issue has this issue no longer presents.