allow login-server to be disabled via spiff templates

For deployments using hostnames instead of static IPs, this allows the list to change scoped by hostnames:

    meta:
      nfs_server:
        address: (( "0.data.cf1." meta.deployment_name ".microbosh" ))
        allow_from_entries:
          - (( "*.*.cf1." meta.deployment_name ".microbosh" ))