Improves link up handling

- trying rehash of the routes for each link up
- redoing reroute only for the routes where rehash fails

Change-Id: I7495277af73d8948300f170fa92cbbfecc338d89
diff --git a/app/src/main/java/org/onosproject/segmentrouting/grouphandler/DefaultGroupHandler.java b/app/src/main/java/org/onosproject/segmentrouting/grouphandler/DefaultGroupHandler.java
index 3431eb6..15513cf 100644
--- a/app/src/main/java/org/onosproject/segmentrouting/grouphandler/DefaultGroupHandler.java
+++ b/app/src/main/java/org/onosproject/segmentrouting/grouphandler/DefaultGroupHandler.java
@@ -541,7 +541,7 @@
         if (!foundNextObjective) {
             log.debug("Cannot find any nextObjectives for route targetSw:{} "
                     + "-> dstSw:{}", targetSw, destSw);
-            return true; // nothing to do, return true so ECMPspg is updated
+            return false; // nothing to do, return false so re-route will be performed
         }
 
         // update the dsNextObjectiveStore with new destinationSet to nextId mappings