Add test for dhm_parse_dhmfile

diff --git a/ChangeLog b/ChangeLog
index b9d44d9..01c9c87 100644
--- a/ChangeLog
+++ b/ChangeLog

@@ -21,6 +21,7 @@
      (found by Gergely Budai)
    * oid_get_numeric_string() used to truncate the output without returning an
      error if the output buffer was just 1 byte too small.
+   * dhm_parse_dhm() (hence dhm_parse_dhmfile()) did not set dhm->len.
 
 = PolarSSL 1.3.5 released on 2014-03-26
 Features