Fixed some errors and inconveniences
Fixed some errors and inconveniences

Major revisions include:
  - added method cluster_get_all_by_parent()
  - added method cluster_get_by_name_and_parent()
  - made cluster_delete() delete all nodes associated
  - manually truncate status_reason field because MySQL won't do it

TODO
  - make cluster_delete capable of delete policy associations

tengqm/senlin-container,tengqm/senlin,stackforge/senlin,openstack/senlin,Alzon/senlin,stackforge/senlin,tengqm/senlin-container,openstack/senlin,Alzon/senlin,tengqm/senlin,openstack/senlin