Default ConsistentMap consistency level to SEQUENTIAL and reenable all Atomix unit tests

Change-Id: Ic04ff81fbaaa7c007f20077391a72fdfa9fd382a
diff --git a/core/store/primitives/src/main/java/org/onosproject/store/primitives/resources/impl/AtomixConsistentMap.java b/core/store/primitives/src/main/java/org/onosproject/store/primitives/resources/impl/AtomixConsistentMap.java
index 4c065a5..14c24a6 100644
--- a/core/store/primitives/src/main/java/org/onosproject/store/primitives/resources/impl/AtomixConsistentMap.java
+++ b/core/store/primitives/src/main/java/org/onosproject/store/primitives/resources/impl/AtomixConsistentMap.java
@@ -236,11 +236,8 @@
     @Override
     public synchronized CompletableFuture<Void> addListener(MapEventListener<String, byte[]> listener) {
         if (!mapEventListeners.isEmpty()) {
-            if (mapEventListeners.add(listener)) {
-                return CompletableFuture.completedFuture(new ChangeListener(listener)).thenApply(v -> null);
-            } else {
-                return CompletableFuture.completedFuture(null);
-            }
+            mapEventListeners.add(listener);
+            return CompletableFuture.completedFuture(null);
         }
         mapEventListeners.add(listener);
         return submit(new AtomixConsistentMapCommands.Listen()).thenApply(v -> null);