Refactored primitive builders to consolidate methods into the base DistributedPrimitiveBuilder

Change-Id: I9a24117b41d1feeb5cf460c6adfa484aabcbb8c1
diff --git a/core/store/primitives/src/main/java/org/onosproject/store/primitives/impl/DefaultDistributedSetBuilder.java b/core/store/primitives/src/main/java/org/onosproject/store/primitives/impl/DefaultDistributedSetBuilder.java
index 6621b4c..8c3e5f3 100644
--- a/core/store/primitives/src/main/java/org/onosproject/store/primitives/impl/DefaultDistributedSetBuilder.java
+++ b/core/store/primitives/src/main/java/org/onosproject/store/primitives/impl/DefaultDistributedSetBuilder.java
@@ -20,7 +20,6 @@
 import org.onosproject.core.ApplicationId;
 import org.onosproject.store.service.AsyncDistributedSet;
 import org.onosproject.store.service.ConsistentMapBuilder;
-import org.onosproject.store.service.DistributedSet;
 import org.onosproject.store.service.Serializer;
 import org.onosproject.store.service.DistributedSetBuilder;
 
@@ -29,7 +28,7 @@
  *
  * @param <E> type for set elements
  */
-public class DefaultDistributedSetBuilder<E> implements DistributedSetBuilder<E> {
+public class DefaultDistributedSetBuilder<E> extends DistributedSetBuilder<E> {
 
     private String name;
     private ConsistentMapBuilder<E, Boolean>  mapBuilder;
@@ -90,12 +89,7 @@
     }
 
     @Override
-    public DistributedSet<E> build() {
-        return new DefaultDistributedSet<E>(buildAsyncSet());
-    }
-
-    @Override
-    public AsyncDistributedSet<E> buildAsyncSet() {
+    public AsyncDistributedSet<E> build() {
         return new DefaultAsyncDistributedSet<E>(mapBuilder.buildAsyncMap(), name, metering);
     }
 }