Now the broadcastPartitionChanges() method check itself the cell_list content.
- If empty, it does nothing.
- If not empty, it generate itself the next PTID and broadcast the changes.

Remove the related XXX.

git-svn-id: https://svn.erp5.org/repos/neo/trunk@1447 71dcc9de-d417-0410-9af5-da40c76e7ee4