implement DeviceProvider triggerProbe() to call after mastership change

Change-Id: I65002296189e6a499ef353255a016b013eb24020
diff --git a/providers/openflow/flow/src/main/java/org/onlab/onos/provider/of/flow/impl/OpenFlowRuleProvider.java b/providers/openflow/flow/src/main/java/org/onlab/onos/provider/of/flow/impl/OpenFlowRuleProvider.java
index 54265ba..d18a72f 100644
--- a/providers/openflow/flow/src/main/java/org/onlab/onos/provider/of/flow/impl/OpenFlowRuleProvider.java
+++ b/providers/openflow/flow/src/main/java/org/onlab/onos/provider/of/flow/impl/OpenFlowRuleProvider.java
@@ -233,6 +233,10 @@
         }
 
         @Override
+        public void switchChanged(Dpid dpid) {
+        }
+
+        @Override
         public void portChanged(Dpid dpid, OFPortStatus status) {
             //TODO: Decide whether to evict flows internal store.
         }
@@ -313,6 +317,7 @@
             }
             return false;
         }
+
     }
 
     private class InstallationFuture implements Future<CompletedBatchOperation> {