[AETHER-1211] Allowing toggling of link labels via Alt-L

Change-Id: I772b6ee0c6c24eeb48466a96a45b44b9ee6eef50
diff --git a/providers/null/src/main/java/org/onosproject/provider/nil/NullProviders.java b/providers/null/src/main/java/org/onosproject/provider/nil/NullProviders.java
index d95943b..ed870f4 100644
--- a/providers/null/src/main/java/org/onosproject/provider/nil/NullProviders.java
+++ b/providers/null/src/main/java/org/onosproject/provider/nil/NullProviders.java
@@ -135,6 +135,7 @@
     private final NullGroupProvider groupProvider = new NullGroupProvider();
     private final NullPacketProvider packetProvider = new NullPacketProvider();
     private final TopologyMutationDriver topologyMutationDriver = new TopologyMutationDriver();
+    private final PortStatsDriver portStatsDriver = new PortStatsDriver();
 
     private DeviceProviderService deviceProviderService;
     private HostProviderService hostProviderService;
@@ -349,6 +350,7 @@
         topologyMutationDriver.start(mutationRate, linkService, deviceService,
                                      linkProviderService, deviceProviderService,
                                      simulator);
+        portStatsDriver.start(deviceService, deviceProviderService);
     }
 
     // Selects the simulator based on the specified name.