LeadershipService and MastershipService/Store APIs return CompletableFutures so that callers can (optionally) chain together dependent operations

Change-Id: Ia00fcb7d98fbfce897527f67ea9690abf6fe846a
diff --git a/providers/lldp/src/test/java/org/onosproject/provider/lldp/impl/LLDPLinkProviderTest.java b/providers/lldp/src/test/java/org/onosproject/provider/lldp/impl/LLDPLinkProviderTest.java
index 2e05ce5..4395914 100644
--- a/providers/lldp/src/test/java/org/onosproject/provider/lldp/impl/LLDPLinkProviderTest.java
+++ b/providers/lldp/src/test/java/org/onosproject/provider/lldp/impl/LLDPLinkProviderTest.java
@@ -30,6 +30,7 @@
 import java.util.List;
 import java.util.Map;
 import java.util.Set;
+import java.util.concurrent.CompletableFuture;
 
 import org.junit.After;
 import org.junit.Before;
@@ -496,8 +497,8 @@
         }
 
         @Override
-        public MastershipRole requestRoleFor(DeviceId deviceId) {
-            return null;
+        public CompletableFuture<MastershipRole> requestRoleFor(DeviceId deviceId) {
+            return CompletableFuture.completedFuture(null);
         }
 
         @Override