DistributedLeadershipManager tracks topic election candidates in addition to
leaders. Includes update to leaders CLI command to list candidates.

part of: Device Mastership store on top of LeadershipService
Reference: ONOS-76

Conflicts:
	core/store/dist/src/main/java/org/onosproject/store/consistent/impl/DistributedLeadershipManager.java

Change-Id: I587bb9e9ad16a9c8392969dde45001181053e5e6
diff --git a/core/api/src/test/java/org/onosproject/cluster/LeadershipServiceAdapter.java b/core/api/src/test/java/org/onosproject/cluster/LeadershipServiceAdapter.java
index 818edb9..02742d4 100644
--- a/core/api/src/test/java/org/onosproject/cluster/LeadershipServiceAdapter.java
+++ b/core/api/src/test/java/org/onosproject/cluster/LeadershipServiceAdapter.java
@@ -15,6 +15,7 @@
  */
 package org.onosproject.cluster;
 
+import java.util.List;
 import java.util.Map;
 import java.util.Set;
 
@@ -62,4 +63,14 @@
     public void removeListener(LeadershipEventListener listener) {
 
     }
+
+    @Override
+    public Map<String, List<NodeId>> getCandidates() {
+        return null;
+    }
+
+    @Override
+    public List<NodeId> getCandidates(String path) {
+        return null;
+    }
 }