Update ironic metadata to handle https on API

This patch updates ironic metadata to work with TLS on ironic API
side.

Change-Id: I07ad586639d24d3166f4e0581e23a5dad75e274c
Related-Prod: PROD-24466
diff --git a/ironic/api/single.yml b/ironic/api/single.yml
index 5eb290b..47b64de 100644
--- a/ironic/api/single.yml
+++ b/ironic/api/single.yml
@@ -38,3 +38,4 @@
           secret_key: ${_param:ironic_memcache_secret_key}
       identity:
         region: ${_param:openstack_region}
+        protocol: ${_param:cluster_internal_protocol}