- fix potential ConflictError on Activity Tool at startup
- fix potential AttributeError in getDistributingNode
- make ProcessingNode._registerNode(distributing=0) disable distributing node
  if current node was distributing
- disable SIGINT for child running storage,
  so that a cluster can shutdown properly

git-svn-id: https://svn.erp5.org/repos/public/erp5/trunk@45693 20353a03-c40f-0410-a6d1-a30d3c3de9de