Implement cinder memcache security strategy

Provides an option to authenticate and optionally encrypt the token
data stored in the cache:
memcache_security_strategy = MAC/ENCRYPT
memcache_secret_key = secret_key

Change-Id: I06dc593e930992291147614d111aa8c34d9f7ee5
Related-Prod: PROD-22099
diff --git a/tests/pillar/control_cluster_intree_wsgi.sls b/tests/pillar/control_cluster_intree_wsgi.sls
index 4c078d4..9ee5d9b 100644
--- a/tests/pillar/control_cluster_intree_wsgi.sls
+++ b/tests/pillar/control_cluster_intree_wsgi.sls
@@ -50,6 +50,10 @@
         port: 11211
       - host: 127.0.0.1
         port: 11211
+      security:
+        enabled: true
+        strategy: ENCRYPT
+        secret_key: secret
     storage:
       engine: storwize
       host: 192.168.0.1