Removed some helper functions in DB event apis
Removed some helper functions in DB event apis

These removed APIs are now replaced by more generic APIs or direct
calls.

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