Split out the logic for deleting a nodedb node.
Split out the logic for deleting a nodedb node.

In order to move to scatter-gather, we need to be able to run just the
tail of deleteNode independently.

Change-Id: If03753e98b423552c8fd6be4d2f5b6b543f3a1af

Tesora/tesora-nodepool,seandst/nodepool,citrix-openstack/nodepool,seandst/nodepool,Tesora/tesora-nodepool,citrix-openstack/nodepool