Added @Beta annotation to the flow objective API.

Change-Id: I4dd91921db1ff533b0ea1e3244dcdbf08b64a499
diff --git a/core/api/src/main/java/org/onosproject/net/flowobjective/ObjectiveContext.java b/core/api/src/main/java/org/onosproject/net/flowobjective/ObjectiveContext.java
index 00e4ed8..5bb2bdc 100644
--- a/core/api/src/main/java/org/onosproject/net/flowobjective/ObjectiveContext.java
+++ b/core/api/src/main/java/org/onosproject/net/flowobjective/ObjectiveContext.java
@@ -15,12 +15,15 @@
  */
 package org.onosproject.net.flowobjective;
 
+import com.google.common.annotations.Beta;
+
 /**
  * The context of a objective that will become the subject of
  * the notification.
  *
  * Implementations of this class must be serializable.
  */
+@Beta
 public interface ObjectiveContext {
 
     default void onSuccess(Objective objective) {}