Add ability to specify custom node name in reclass.

In terms of PR to salt formula:
https://github.com/salt-formulas/salt-formula-salt/pull/44
I would like to introduce this changes in model.
diff --git a/salt/control/cluster/openstack_database_cluster.yml b/salt/control/cluster/openstack_database_cluster.yml
index 50eb0d3..2a00308 100644
--- a/salt/control/cluster/openstack_database_cluster.yml
+++ b/salt/control/cluster/openstack_database_cluster.yml
@@ -13,14 +13,17 @@
           engine: virt
           node:
             dbs01:
+              name: ${_param:openstack_database_node01_hostname}
               provider: ${_param:infra_kvm_node01_hostname}.${_param:cluster_domain}
               image: ${_param:salt_control_trusty_image}
               size: openstack.database
             dbs02:
+              name: ${_param:openstack_database_node02_hostname}
               provider: ${_param:infra_kvm_node02_hostname}.${_param:cluster_domain}
               image: ${_param:salt_control_trusty_image}
               size: openstack.database
             dbs03:
+              name: ${_param:openstack_database_node03_hostname}
               provider: ${_param:infra_kvm_node03_hostname}.${_param:cluster_domain}
               image: ${_param:salt_control_trusty_image}
               size: openstack.database