ONOS-2003 Fixing intent reroute after cluster change

Objective trackers update when partitions are shuffled to
track "local" intents.

Change-Id: I7cd9e4a935ddbc94813d5067d4febc084a89f508
diff --git a/core/api/src/main/java/org/onosproject/net/intent/PartitionService.java b/core/api/src/main/java/org/onosproject/net/intent/PartitionService.java
index e963abc..c636cd2 100644
--- a/core/api/src/main/java/org/onosproject/net/intent/PartitionService.java
+++ b/core/api/src/main/java/org/onosproject/net/intent/PartitionService.java
@@ -40,4 +40,18 @@
     NodeId getLeader(Key intentKey);
 
     // TODO add API for rebalancing partitions
+
+    /**
+     * Registers a event listener to be notified of partition events.
+     *
+     * @param listener listener that will asynchronously notified of partition events.
+     */
+    void addListener(PartitionEventListener listener);
+
+    /**
+     * Unregisters a event listener for partition events.
+     *
+     * @param listener listener to be removed.
+     */
+    void removeListener(PartitionEventListener listener);
 }