Fix changelog for ssl_server2.c usage fix
diff --git a/ChangeLog b/ChangeLog
index d5ed6ad..98776ec 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -5,6 +5,7 @@
 Bugfix
    * Fix memory leak in ssl_set_hostname() when called multiple times.
      Found by projectgus and jethrogb, #836.
+   * Fix usage help in ssl_server2 example. Found and fixed by Bei Lin.
 
 = mbed TLS 1.3.21 branch released 2017-08-10