Initial cut at Leadership Manager

Change-Id: I658c6fca3dc6f686e0f7facc9e7b443679ebae1e

Change-Id: I293906add41ff4310e3584847d806345e0312703

Change-Id: I7fb13a72ba4aef10d7c2262b96e0df64efecfcef
diff --git a/core/store/dist/src/main/java/org/onlab/onos/store/service/impl/DistributedLock.java b/core/store/dist/src/main/java/org/onlab/onos/store/service/impl/DistributedLock.java
index 7575ed9..74bff8b 100644
--- a/core/store/dist/src/main/java/org/onlab/onos/store/service/impl/DistributedLock.java
+++ b/core/store/dist/src/main/java/org/onlab/onos/store/service/impl/DistributedLock.java
@@ -6,7 +6,6 @@
 import java.util.UUID;
 import java.util.concurrent.CompletableFuture;
 import java.util.concurrent.ExecutionException;
-import java.util.concurrent.Future;
 import java.util.concurrent.TimeUnit;
 import java.util.concurrent.TimeoutException;
 import java.util.concurrent.atomic.AtomicBoolean;
@@ -62,7 +61,7 @@
     }
 
     @Override
-    public Future<Void> lockAsync(int leaseDurationMillis) {
+    public CompletableFuture<Void> lockAsync(int leaseDurationMillis) {
         if (isLocked() || tryLock(leaseDurationMillis)) {
             return CompletableFuture.<Void>completedFuture(null);
         }