Fix to reinstall flow rules when they are missing in FlowRuleService.

Change-Id: I1e7e0d62e27012cd090f3a72eb92eadc85afafdf
diff --git a/core/api/src/main/java/org/onosproject/net/flow/FlowRuleService.java b/core/api/src/main/java/org/onosproject/net/flow/FlowRuleService.java
index 2b29504..9cada03 100644
--- a/core/api/src/main/java/org/onosproject/net/flow/FlowRuleService.java
+++ b/core/api/src/main/java/org/onosproject/net/flow/FlowRuleService.java
@@ -64,6 +64,14 @@
     }
 
     /**
+     * Returns the stored flow.
+     *
+     * @param rule the rule to look for
+     * @return a flow rule
+     */
+    FlowEntry getFlowEntry(FlowRule rule);
+
+    /**
      * Returns the collection of flow entries applied on the specified device.
      * This will include flow rules which may not yet have been applied to
      * the device.