Update default for running_deleted_instance_action

Update the default value of running_deleted_instance_action to 'reap'
from 'log'.  Consensus seems to be that this is what most people expect.

DocImpact

http://lists.openstack.org/pipermail/openstack-dev/2013-October/016153.html

Change-Id: I24990e20c8b85fb8b7ce15c229f99f5b0281f103
Merge "Update default for running_deleted_instance_action"