Enable oslo.cache library

    Add gnocchi:server:cache metadata:

          cache:
            engine: memcached
            expiration_time: 600
            backend_argument:
              memcached_expire_time:
                value: 660
            members:
            - host:
              port: 11211
            - host:
              port: 11211
            - host:
              port: 11211

    Enable oslo.cache in the gnocchi.conf file

    Related-Prod: PROD-26960

Change-Id: I1ccde3bd2e0ba907188ac40cb9e5dd45e606ec5b
diff --git a/metadata/service/server/single.yml b/metadata/service/server/single.yml
index fb7da38..6eb5d52 100644
--- a/metadata/service/server/single.yml
+++ b/metadata/service/server/single.yml
@@ -22,3 +22,12 @@
         password: ${_param:keystone_gnocchi_password}
         tenant: service
         auth_type: password
+      cache:
+        engine: memcached
+        expiration_time: 600
+        backend_argument:
+          memcached_expire_time:
+            value: 660
+        members:
+        - host: ${_param:single_address}
+          port: 11211