ONOS-2440: Simplify DistributedQueue implementation by leveraging state change notification support

Change-Id: Id0a48f07535d8b7e1d0f964bd1c0623ca81d4605
diff --git a/core/store/dist/src/main/java/org/onosproject/store/consistent/impl/DefaultAsyncConsistentMap.java b/core/store/dist/src/main/java/org/onosproject/store/consistent/impl/DefaultAsyncConsistentMap.java
index c9311c9..9082ba6 100644
--- a/core/store/dist/src/main/java/org/onosproject/store/consistent/impl/DefaultAsyncConsistentMap.java
+++ b/core/store/dist/src/main/java/org/onosproject/store/consistent/impl/DefaultAsyncConsistentMap.java
@@ -47,7 +47,7 @@
 import java.util.stream.Collectors;
 
 import static com.google.common.base.Preconditions.checkNotNull;
-import static org.onosproject.store.consistent.impl.StateMachineUpdate.Target.MAP;
+import static org.onosproject.store.consistent.impl.StateMachineUpdate.Target.MAP_UPDATE;
 import static org.onosproject.store.consistent.impl.StateMachineUpdate.Target.TX_COMMIT;
 import static org.slf4j.LoggerFactory.getLogger;
 
@@ -122,7 +122,7 @@
         this.purgeOnUninstall = purgeOnUninstall;
         this.database.registerConsumer(update -> {
             SharedExecutors.getSingleThreadExecutor().execute(() -> {
-                if (update.target() == MAP) {
+                if (update.target() == MAP_UPDATE) {
                     Result<UpdateResult<String, byte[]>> result = update.output();
                     if (result.success() && result.value().mapName().equals(name)) {
                         MapEvent<K, V> mapEvent = result.value().<K, V>map(this::dK, serializer::decode).toMapEvent();