Deprecate HexDump

- Part of reducing dependency to netty 3

Change-Id: I64cf70a03ffc61ca9a9b263e1fe88dbbb9a5389f
diff --git a/utils/misc/src/main/java/org/onlab/util/HexDump.java b/utils/misc/src/main/java/org/onlab/util/HexDump.java
index 43857c2..02d68c7 100644
--- a/utils/misc/src/main/java/org/onlab/util/HexDump.java
+++ b/utils/misc/src/main/java/org/onlab/util/HexDump.java
@@ -21,7 +21,10 @@
 
 /**
  * HexDump class an utility to dump buffer in hex format.
+ *
+ * @deprecated in 1.11.0
  */
+@Deprecated
 public final class HexDump {
     protected static final Logger log = LoggerFactory.getLogger(HexDump.class);