Add cinder keystone client opts to config reference

This adds the config reference items to cinder for things like the
insecure flag, and ca options. This mirrors what we have for services
like glance and ironic.

Change-Id: If3c00a223fbfcb34fd92f8315f2a59bcb819e79e
Closes-Bug: #1615666

nova/conf/cinder.py

@@ -106,5 +106,7 @@ def register_opts(conf):
 
 def list_opts():
     return {
-        cinder_group.name: cinder_opts
+        cinder_group.name: (
+            cinder_opts +
+            ks_loading.get_session_conf_options())
     }