[JM-1217] Added ability to register multiple components on the same JID if allowMultiple="true" is specified as an attribute in the stream header.  <stream:stream ...... allowMultiple="yes">

git-svn-id: http://svn.igniterealtime.org/svn/repos/openfire/trunk@9771 b35dd754-fafc-0310-a699-88a17e54d16e