fix log message

Change-Id: Ia46b5ad2564bff37bf344938809c61960d1930c3
diff --git a/openflow/api/src/main/java/org/onosproject/openflow/controller/DefaultOpenFlowPacketContext.java b/openflow/api/src/main/java/org/onosproject/openflow/controller/DefaultOpenFlowPacketContext.java
index 238c400..af92a1d 100644
--- a/openflow/api/src/main/java/org/onosproject/openflow/controller/DefaultOpenFlowPacketContext.java
+++ b/openflow/api/src/main/java/org/onosproject/openflow/controller/DefaultOpenFlowPacketContext.java
@@ -104,7 +104,7 @@
         } catch (BufferUnderflowException | NullPointerException |
                 DeserializationException e) {
             Logger log = LoggerFactory.getLogger(getClass());
-            log.warn("packet deserialization problem : {}", e.getMessage());
+            log.error("packet deserialization problem : {}", e.getMessage());
             return null;
         }
     }