Fix deletion policy candidate selection
Fix deletion policy candidate selection

There are in total 4 policies supported currently. That leaves no chance
of the candidate selection function to fall out the four branches. This
patch deletes some dead code.

Change-Id: Ie23902032fff18fdcc48fa5bb5fd99babc3042b0

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