[master] update ChangeLog

ChangeLog

@@ -1,3 +1,8 @@
+  199.  [func]           ocean
+        Cache negative responses (NXDOMAIN/NODATA) from authoritative
+        server for recursive resolver.
+        (Trac #493, git f8fb852bc6aef292555063590c361f01cf29e5ca)
+
   198.	[bug]		jinmei
 	b10-auth, src/lib/datasrc: fixed a bug where hot spot cache failed
 	to reuse cached SOA for negative responses.  Due to this bug