Allowed flows to be permanent

Change-Id: I61952fe4cbad98be53094c7ec4a474868384b616
diff --git a/core/net/src/main/java/org/onlab/onos/net/flow/impl/FlowRuleManager.java b/core/net/src/main/java/org/onlab/onos/net/flow/impl/FlowRuleManager.java
index 525946e..67e0867 100644
--- a/core/net/src/main/java/org/onlab/onos/net/flow/impl/FlowRuleManager.java
+++ b/core/net/src/main/java/org/onlab/onos/net/flow/impl/FlowRuleManager.java
@@ -327,6 +327,10 @@
             if (storedRule == null) {
                 return false;
             }
+            if (storedRule.isPermanent()) {
+                return true;
+            }
+
             final long timeout = storedRule.timeout() * 1000;
             final long currentTime = System.currentTimeMillis();
             if (storedRule.packets() != swRule.packets()) {