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/store/dist/src/main/java/org/onosproject/store/packet/impl/DistributedPacketStore.java b/core/store/dist/src/main/java/org/onosproject/store/packet/impl/DistributedPacketStore.java
index f3bd0b5..7e63d89 100644
--- a/core/store/dist/src/main/java/org/onosproject/store/packet/impl/DistributedPacketStore.java
+++ b/core/store/dist/src/main/java/org/onosproject/store/packet/impl/DistributedPacketStore.java
@@ -118,7 +118,7 @@
     public void activate() {
         messageHandlingExecutor = Executors.newFixedThreadPool(
                 messageHandlerThreadPoolSize,
-                groupedThreads("onos/store/packet", "message-handlers"));
+                groupedThreads("onos/store/packet", "message-handlers", log));
 
         communicationService.<OutboundPacket>addSubscriber(PACKET_OUT_SUBJECT,
                 SERIALIZER::decode,