Lower log level

- periodic non-error log to trace
- Host event to debug

Change-Id: I1a3e746f4cafe72dbaa648ac379a0548a93445e4
diff --git a/core/store/dist/src/main/java/org/onlab/onos/store/link/impl/GossipLinkStore.java b/core/store/dist/src/main/java/org/onlab/onos/store/link/impl/GossipLinkStore.java
index d4b0916..2ae6cd8 100644
--- a/core/store/dist/src/main/java/org/onlab/onos/store/link/impl/GossipLinkStore.java
+++ b/core/store/dist/src/main/java/org/onlab/onos/store/link/impl/GossipLinkStore.java
@@ -638,7 +638,7 @@
                         .toList();
 
                 if (nodeIds.size() == 1 && nodeIds.get(0).equals(self)) {
-                    log.debug("No other peers in the cluster.");
+                    log.trace("No other peers in the cluster.");
                     return;
                 }
 
@@ -796,7 +796,7 @@
 
         @Override
         public void handle(ClusterMessage message) {
-            log.debug("Received Link Anti-Entropy advertisement from peer: {}", message.sender());
+            log.trace("Received Link Anti-Entropy advertisement from peer: {}", message.sender());
             LinkAntiEntropyAdvertisement advertisement = SERIALIZER.decode(message.payload());
             handleAntiEntropyAdvertisement(advertisement);
         }