DatabaseManager: fix scope

Change-Id: I1e01623acf1a7197aea3e8d9dbc180c9b265f415
diff --git a/core/store/dist/src/main/java/org/onlab/onos/store/service/impl/ClusterMessagingProtocol.java b/core/store/dist/src/main/java/org/onlab/onos/store/service/impl/ClusterMessagingProtocol.java
index d88a214..6de66bc 100644
--- a/core/store/dist/src/main/java/org/onlab/onos/store/service/impl/ClusterMessagingProtocol.java
+++ b/core/store/dist/src/main/java/org/onlab/onos/store/service/impl/ClusterMessagingProtocol.java
@@ -69,10 +69,10 @@
     private final Logger log = getLogger(getClass());
 
     @Reference(cardinality = ReferenceCardinality.MANDATORY_UNARY)
-    ClusterService clusterService;
+    protected ClusterService clusterService;
 
     @Reference(cardinality = ReferenceCardinality.MANDATORY_UNARY)
-    ClusterCommunicationService clusterCommunicator;
+    protected ClusterCommunicationService clusterCommunicator;
 
     public static final MessageSubject COPYCAT_PING =
             new MessageSubject("copycat-raft-consensus-ping");