add changelog for Pylons#241

Author: mmerickel

CHANGES.txt

@@ -9,6 +9,7 @@ Bugfixes
   response when a client hangs up.
   See https://github.com/Pylons/waitress/pull/238
   and https://github.com/Pylons/waitress/pull/240
+  and https://github.com/Pylons/waitress/pull/241
 
 - When a client closes a socket unexpectedly there was potential for memory
   leaks in which data was written to the buffers after they were closed,