Implement neutron 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: I7f623586023c8b0605bb77977a28d6b7c47e5287
Related-Prod: PROD-22099
diff --git a/tests/pillar/control_cluster.sls b/tests/pillar/control_cluster.sls
index 1a1d30b..2d70ca2 100644
--- a/tests/pillar/control_cluster.sls
+++ b/tests/pillar/control_cluster.sls
@@ -59,4 +59,16 @@
       create_subnet: 'rule:admin_or_network_owner'
       'get_network:queue_id': 'rule:admin_only'
       'create_network:shared':
-
+    cache:
+      engine: memcached
+      members:
+      - host: 127.0.0.1
+        port: 11211
+      - host: 127.0.0.1
+        port: 11211
+      - host: 127.0.0.1
+        port: 11211
+      security:
+        enabled: true
+        strategy: ENCRYPT
+        secret_key: secret