This allows to avoid redundant XML namespaces within IQs, like for
example here:
<iq xmlns='jabber:client' id='EKP8I-1' type='set'>
<jingle xmlns='urn:xmpp:jingle:1' action='content-accept' sid='MySession'>
<content xmlns='urn:xmpp:jingle:1' creator='initiator' name='Hello world'>
</content>
</jingle>
</iq>
Fixes SMACK-917
Reported-by: Jonathan Lennox