Fixed method returning disco items to return top level items only when node is null.
Fixed method returning disco items to return top level items only when node is null.

git-svn-id: 2c879fc15d19d1499d1f18f59be0b17f5319b06e@156 5cc3df33-c827-0410-82ff-b820e365a07a

getintouchapp/tigase-muc,Smartupz/tigase-muc,getintouchapp/tigase-muc