Fix duplication in Changelog introduced by merge
diff --git a/ChangeLog b/ChangeLog
index 796cc51..d4ebea0 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -40,8 +40,6 @@
      encoded X509 CSRs. The overflow would enable maliciously constructed CSRs
      to bypass the version verification check. Found by Peng Li/Yueh-Hsun Lin,
      KNOX Security, Samsung Research America
-   * Add a check if iv_len is zero, and return an error if it is zero. reported
-     by roberto. #716
 
 = mbed TLS 2.1.8 branch released 2017-06-21