Intents are now removed after being withdrawn.

Change-Id: I7574fe94add00abf58c71c6122bb3dc5aafa0f79
diff --git a/core/api/src/main/java/org/onlab/onos/net/intent/IntentStore.java b/core/api/src/main/java/org/onlab/onos/net/intent/IntentStore.java
index a2248a2..3af59c1 100644
--- a/core/api/src/main/java/org/onlab/onos/net/intent/IntentStore.java
+++ b/core/api/src/main/java/org/onlab/onos/net/intent/IntentStore.java
@@ -42,9 +42,8 @@
      * Removes the specified intent from the inventory.
      *
      * @param intentId intent identification
-     * @return removed state transition event or null if intent was not found
      */
-    IntentEvent removeIntent(IntentId intentId);
+    void removeIntent(IntentId intentId);
 
     /**
      * Returns the number of intents in the store.
@@ -103,8 +102,6 @@
      */
     List<Intent> getInstallableIntents(IntentId intentId);
 
-    // TODO: this should be triggered from with the store as a result of removeIntent call
-
     /**
      * Removes any installable intents which resulted from compilation of the
      * specified original intent.