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/drivers/default/src/main/java/org/onosproject/driver/pipeline/SpringOpenTTP.java b/drivers/default/src/main/java/org/onosproject/driver/pipeline/SpringOpenTTP.java
index ad4a095..6dab296 100644
--- a/drivers/default/src/main/java/org/onosproject/driver/pipeline/SpringOpenTTP.java
+++ b/drivers/default/src/main/java/org/onosproject/driver/pipeline/SpringOpenTTP.java
@@ -132,7 +132,8 @@
     private ScheduledExecutorService groupChecker = Executors
             .newScheduledThreadPool(2,
                                     groupedThreads("onos/pipeliner",
-                                                   "spring-open-%d"));
+                                                   "spring-open-%d",
+                                                   log));
     protected KryoNamespace appKryo = new KryoNamespace.Builder()
             .register(KryoNamespaces.API)
             .register(GroupKey.class)