Replace hardcoded provider for salt.control state

In case of using custom names for KVM nodes provided in
cookiecutter.json, after applying state salt.control it is not creating
VM's because provider is kvm01, kvm02, kvm03.

Change-Id: I4a7c1692f3e95fae6fc336ce605964cf78c47ea9
diff --git a/salt/control/cluster/openstack_telemetry_cluster.yml b/salt/control/cluster/openstack_telemetry_cluster.yml
index 463a2ca..5d714fc 100644
--- a/salt/control/cluster/openstack_telemetry_cluster.yml
+++ b/salt/control/cluster/openstack_telemetry_cluster.yml
@@ -13,14 +13,14 @@
           engine: virt
           node:
             mdb01:
-              provider: kvm01.${_param:cluster_domain}
+              provider: ${_param:infra_kvm_node01_hostname}.${_param:cluster_domain}
               image: ${_param:salt_control_trusty_image}
               size: openstack.telemetry
             mdb02:
-              provider: kvm02.${_param:cluster_domain}
+              provider: ${_param:infra_kvm_node02_hostname}.${_param:cluster_domain}
               image: ${_param:salt_control_trusty_image}
               size: openstack.telemetry
             mdb03:
-              provider: kvm03.${_param:cluster_domain}
+              provider: ${_param:infra_kvm_node03_hostname}.${_param:cluster_domain}
               image: ${_param:salt_control_trusty_image}
               size: openstack.telemetry