Instances spin up with "default" name

When spinning up instances, they are all created with the name "default" (at least in Openstack, if that's not the case elsewhere then we have a different issue).  

It appears the issue is related to:

https://github.com/opscode/chef-metal-fog/blob/master/lib/chef_metal_fog/fog_provisioner.rb#L208

It looks like it's pulling the name from `machine_batch[default]` rather than the actual `node['name']`.

If this was intentional, then I'll need to keep digging!  Thanks!