Fix the allocation distribution
Fix the allocation distribution

The new simpler method for calculating the weight of the targets
is a little too simple and can miss allocating nodes.  Make the
weight change as the algorithm walks through the target list
to ensure that everything is allocated somewhere.

Change-Id: I98f72c69cf2793aa012f330219cd850a5d4ceab2

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