DeviceManager queries MastershipService

Change-Id: I0d391ecb7f0b1e4cced99cfe8083b46f74ee35bb
diff --git a/core/api/src/main/java/org/onlab/onos/cluster/MastershipEvent.java b/core/api/src/main/java/org/onlab/onos/cluster/MastershipEvent.java
index 2a5e62e..15811fb 100644
--- a/core/api/src/main/java/org/onlab/onos/cluster/MastershipEvent.java
+++ b/core/api/src/main/java/org/onlab/onos/cluster/MastershipEvent.java
@@ -8,6 +8,8 @@
  */
 public class MastershipEvent extends AbstractEvent<MastershipEvent.Type, DeviceId> {
 
+    //do we worry about explicitly setting slaves/equals? probably not,
+    //to keep it simple
     NodeId master;
 
     /**
@@ -28,7 +30,7 @@
      * @param device event device subject
      * @param master master ID subject
      */
-    protected MastershipEvent(Type type, DeviceId device, NodeId master) {
+    public MastershipEvent(Type type, DeviceId device, NodeId master) {
         super(type, device);
         this.master = master;
     }
@@ -42,7 +44,7 @@
      * @param master master ID subject
      * @param time   occurrence time
      */
-    protected MastershipEvent(Type type, DeviceId device, NodeId master, long time) {
+    public MastershipEvent(Type type, DeviceId device, NodeId master, long time) {
         super(type, device, time);
         this.master = master;
     }