Revert dropped when error returned.

Remove null set
pacemaker cluster members should be on Cluster Management network
Merge pull request #302 from knowncitizen/nics_drag_fix

Revert dropped when error returned.
calculate nova network size

This gets rid of the default '256' nova network size, which required larger
fixed tenant ranges when using vlans. Now, network size is calculated
from the fixed tenant range and the number of networks, to make sure that
the networks all fit within the same address space.

This also includes validation to make sure that the fixed range is
large enough to allow for a minimum network size of 4.
Merge pull request #315 from sseago/cluster_mgmt

pacemaker cluster members should be on Cluster Management network
Merge pull request #320 from sseago/nova-network-size

calculate nova network size