log uncaught Exception

- Use execute instead of submit so that uncaught Exception will
  be dealt and logged by ExecutorService's handler.
- Use component's own logger

Change-Id: I761264aea00748980929b5048e111756776dd2f6
diff --git a/core/net/src/main/java/org/onosproject/net/topology/impl/DefaultTopologyProvider.java b/core/net/src/main/java/org/onosproject/net/topology/impl/DefaultTopologyProvider.java
index 1fac99f..5adec7c 100644
--- a/core/net/src/main/java/org/onosproject/net/topology/impl/DefaultTopologyProvider.java
+++ b/core/net/src/main/java/org/onosproject/net/topology/impl/DefaultTopologyProvider.java
@@ -124,7 +124,7 @@
     @Activate
     public synchronized void activate(ComponentContext context) {
         cfgService.registerProperties(DefaultTopologyProvider.class);
-        executor = newFixedThreadPool(MAX_THREADS, groupedThreads("onos/topo", "build-%d"));
+        executor = newFixedThreadPool(MAX_THREADS, groupedThreads("onos/topo", "build-%d", log));
         accumulator = new TopologyChangeAccumulator();
         logConfig("Configured");