Centralize setting internal_protocol

Internal Openstack APIs may be encrypted with https. This patch
centralize setting internal API protocol among services by
setting one of depending if cluster or single models are used:
  cluster_internal_protocol: 'https'
  internal_protocol: 'https'

Change-Id: I2baff79cd5851678559d7de47460fdd2031f70ee
diff --git a/cinder/volume/single.yml b/cinder/volume/single.yml
index de468ba..1b9948d 100644
--- a/cinder/volume/single.yml
+++ b/cinder/volume/single.yml
@@ -1,6 +1,8 @@
 classes:
 - service.cinder.volume.single
 parameters:
+  _param:
+    cluster_internal_protocol: 'http'
   linux:
     system:
       package:
@@ -21,3 +23,4 @@
           - host: ${_param:openstack_message_queue_node03_address}
       identity:
         host: ${_param:openstack_control_address}
+        protocol: ${_param:cluster_internal_protocol}