Bugfix and improvement of SR config loading

Change-Id: If17af7ff1fbd3cb712e59cce930ef11146bdbf2e
diff --git a/apps/segmentrouting/src/main/java/org/onosproject/segmentrouting/NetworkConfigEventHandler.java b/apps/segmentrouting/src/main/java/org/onosproject/segmentrouting/NetworkConfigEventHandler.java
index afb7ec9..f32cd2d9 100644
--- a/apps/segmentrouting/src/main/java/org/onosproject/segmentrouting/NetworkConfigEventHandler.java
+++ b/apps/segmentrouting/src/main/java/org/onosproject/segmentrouting/NetworkConfigEventHandler.java
@@ -137,12 +137,7 @@
         if (config == null) {
             return ImmutableSet.of();
         }
-
-        HashSet<MacAddress> macAddresses = new HashSet<>();
-        config.vRouterMacs().forEach(mac -> {
-            macAddresses.add(mac);
-        });
-        return ImmutableSet.copyOf(macAddresses);
+        return ImmutableSet.copyOf(config.vRouterMacs());
     }
 
     private boolean isEdge(DeviceId deviceId) {