Remove deprecated API from virtual network flow rule store

Change-Id: I3de9a1bf56d87f0c95843f61ccc3f8f2e37d1c5b
diff --git a/incubator/store/src/main/java/org/onosproject/incubator/store/virtual/impl/SimpleVirtualFlowRuleStore.java b/incubator/store/src/main/java/org/onosproject/incubator/store/virtual/impl/SimpleVirtualFlowRuleStore.java
index 4b22d9e..eeb3a7c 100644
--- a/incubator/store/src/main/java/org/onosproject/incubator/store/virtual/impl/SimpleVirtualFlowRuleStore.java
+++ b/incubator/store/src/main/java/org/onosproject/incubator/store/virtual/impl/SimpleVirtualFlowRuleStore.java
@@ -177,8 +177,7 @@
                 .transformAndConcat(Collections::unmodifiableList);
     }
 
-    @Override
-    public void storeFlowRule(NetworkId networkId, FlowRule rule) {
+    private void storeFlowRule(NetworkId networkId, FlowRule rule) {
         storeFlowRuleInternal(networkId, rule);
     }