Enable oslo.cache library

Add barbican:server:cache metadata

      cache:
        engine: memcached
        expiration_time: 600
        backend_argument:
          memcached_expire_time:
            value: 660

Enable oslo.cache in the barbican.conf file

Change-Id: I2d7c319fe1fb788c9d583f8b17dbf159597dac78
Related-Prod: PROD-26960
diff --git a/tests/pillar/control_cluster.sls b/tests/pillar/control_cluster.sls
index 7dd138d..e485a24 100644
--- a/tests/pillar/control_cluster.sls
+++ b/tests/pillar/control_cluster.sls
@@ -78,6 +78,11 @@
       - host: 10.10.10.12
         port: 5672
     cache:
+      engine: memcached
+      expiration_time: 600
+      backend_argument:
+        memcached_expire_time:
+          value: 660
       members:
       - host: 10.10.10.10
         port: 11211