Remove bridges and associated flow rules when removing k8s nodes

Change-Id: Iab54503a4bb75874f69e8e1623bb11c66cad9eee
(cherry picked from commit dc1df642f320123f8b31d6f2a62e7ac6498c87d0)
diff --git a/apps/k8s-node/api/src/main/java/org/onosproject/k8snode/api/K8sNodeHandler.java b/apps/k8s-node/api/src/main/java/org/onosproject/k8snode/api/K8sNodeHandler.java
index 0ef7302..3ad369f 100644
--- a/apps/k8s-node/api/src/main/java/org/onosproject/k8snode/api/K8sNodeHandler.java
+++ b/apps/k8s-node/api/src/main/java/org/onosproject/k8snode/api/K8sNodeHandler.java
@@ -75,4 +75,11 @@
      * @param k8sNode kubernetes node
      */
     void processPostOnBoardState(K8sNode k8sNode);
+
+    /**
+     * Processes the given node for off boarded state.
+     *
+     * @param k8sNode kubernetes node
+     */
+    void processOffBoardedState(K8sNode k8sNode);
 }