update ChangeLog

Update ChangeLog with suggested rephrasing
diff --git a/ChangeLog b/ChangeLog
index 4249de7..a00ad1b 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -138,7 +138,7 @@
    * Put the Cryptographic API outside of the XXX_ALT macro check, so
      alternative header file will not need to redefined the same API,
      and to force alternative implementer to use the same API.
-
+     
 = mbed TLS 2.7.0 branch released 2018-02-03
 
 Security