Allow deploying of more than one vmware compute node

The restriction to only one compute node is bad for HA/scale
out reasons, and it seems to be possible to deploy multiple
computes just fine..
Nova Compute with VMware VCDriver is only proxy to VMware vCenter, it has nothing with production workload. I was thinking only from user point of view to tell him that assigning more nodes to this role is worthless. But if you think that it might be reasonable, we can go with unlimited number of Nova Computes for VMware.