max active keys for fernet

Change-Id: I4fafaee9c6203139f276b68c21904ec400133003
diff --git a/tests/pillar/single_fernet.sls b/tests/pillar/single_fernet.sls
index 15f61f3..e9f90eb 100644
--- a/tests/pillar/single_fernet.sls
+++ b/tests/pillar/single_fernet.sls
@@ -25,6 +25,7 @@
       engine: fernet
       expiration: 86400
       location: /etc/keystone/fernet-keys/
+      max_active_keys: 4
     cache:
       engine: memcached
       members: