Changing log level from warn to debug in Stats Store.

Change-Id: I7651427d317813775a2c729682001fb888b45f1c
Note: Optical flows don't have stats.
diff --git a/core/store/dist/src/main/java/org/onlab/onos/store/statistic/impl/DistributedStatisticStore.java b/core/store/dist/src/main/java/org/onlab/onos/store/statistic/impl/DistributedStatisticStore.java
index a7a3a02..cc432a0 100644
--- a/core/store/dist/src/main/java/org/onlab/onos/store/statistic/impl/DistributedStatisticStore.java
+++ b/core/store/dist/src/main/java/org/onlab/onos/store/statistic/impl/DistributedStatisticStore.java
@@ -275,7 +275,7 @@
     private ConnectPoint buildConnectPoint(FlowRule rule) {
         PortNumber port = getOutput(rule);
         if (port == null) {
-            log.warn("Rule {} has no output.", rule);
+            log.debug("Rule {} has no output.", rule);
             return null;
         }
         ConnectPoint cp = new ConnectPoint(rule.deviceId(), port);
diff --git a/core/store/trivial/src/main/java/org/onlab/onos/store/trivial/impl/SimpleStatisticStore.java b/core/store/trivial/src/main/java/org/onlab/onos/store/trivial/impl/SimpleStatisticStore.java
index 0d4da5c..16577e8 100644
--- a/core/store/trivial/src/main/java/org/onlab/onos/store/trivial/impl/SimpleStatisticStore.java
+++ b/core/store/trivial/src/main/java/org/onlab/onos/store/trivial/impl/SimpleStatisticStore.java
@@ -154,7 +154,7 @@
     private ConnectPoint buildConnectPoint(FlowRule rule) {
         PortNumber port = getOutput(rule);
         if (port == null) {
-            log.warn("Rule {} has no output.", rule);
+            log.debug("Rule {} has no output.", rule);
             return null;
         }
         ConnectPoint cp = new ConnectPoint(rule.deviceId(), port);