Code clean up: Removed unused code. Fixed comments. Renamed some files.

Change-Id: I78ca1f4a973c3b5356f749680ebe0f4ccde01279
diff --git a/core/store/dist/src/main/java/org/onosproject/store/statistic/impl/DistributedFlowStatisticStore.java b/core/store/dist/src/main/java/org/onosproject/store/statistic/impl/DistributedFlowStatisticStore.java
index f8e7c71..74ab40b 100644
--- a/core/store/dist/src/main/java/org/onosproject/store/statistic/impl/DistributedFlowStatisticStore.java
+++ b/core/store/dist/src/main/java/org/onosproject/store/statistic/impl/DistributedFlowStatisticStore.java
@@ -17,6 +17,7 @@
 package org.onosproject.store.statistic.impl;
 
 import com.google.common.base.Objects;
+
 import org.apache.felix.scr.annotations.Activate;
 import org.apache.felix.scr.annotations.Component;
 import org.apache.felix.scr.annotations.Deactivate;
@@ -38,6 +39,7 @@
 import org.onosproject.net.flow.instructions.Instructions;
 import org.onosproject.net.statistic.FlowStatisticStore;
 import org.onosproject.store.cluster.messaging.ClusterCommunicationService;
+import org.onosproject.store.cluster.messaging.MessageSubject;
 import org.onosproject.store.serializers.KryoNamespaces;
 import org.onosproject.store.serializers.StoreSerializer;
 import org.osgi.service.component.ComponentContext;
@@ -59,8 +61,6 @@
 import static com.google.common.base.Strings.isNullOrEmpty;
 import static org.onlab.util.Tools.get;
 import static org.onlab.util.Tools.groupedThreads;
-import static org.onosproject.store.statistic.impl.StatisticStoreMessageSubjects.GET_CURRENT;
-import static org.onosproject.store.statistic.impl.StatisticStoreMessageSubjects.GET_PREVIOUS;
 import static org.slf4j.LoggerFactory.getLogger;
 
 /**
@@ -89,6 +89,9 @@
     private Map<ConnectPoint, Set<FlowEntry>> current =
             new ConcurrentHashMap<>();
 
+    public static final MessageSubject GET_CURRENT = new MessageSubject("peer-return-current");
+    public static final MessageSubject GET_PREVIOUS = new MessageSubject("peer-return-previous");
+
     protected static final StoreSerializer SERIALIZER = StoreSerializer.using(KryoNamespaces.API);
 
     private NodeId local;