ONOS-3763 Change flow state to PENDING_ADD when retrying

Will emit a RULE_UPDATE event if the state is changed.
Update unit test accordingly.

Change-Id: Ie84778c62f52f15b7636d41db246814145e73f77
diff --git a/core/net/src/main/java/org/onosproject/net/flow/impl/FlowRuleManager.java b/core/net/src/main/java/org/onosproject/net/flow/impl/FlowRuleManager.java
index de92894..570383a 100644
--- a/core/net/src/main/java/org/onosproject/net/flow/impl/FlowRuleManager.java
+++ b/core/net/src/main/java/org/onosproject/net/flow/impl/FlowRuleManager.java
@@ -305,6 +305,7 @@
                     break;
                 case ADDED:
                 case PENDING_ADD:
+                    event = store.pendingFlowRule(flowRule);
                     try {
                         frp.applyFlowRule(flowRule);
                     } catch (UnsupportedOperationException e) {