Fix ECDSA corner case: missing reduction mod N

No security issue, can cause valid signatures to be rejected.

Reported by DualTachyon on github.
diff --git a/ChangeLog b/ChangeLog
index 7c0471b..bcbd7c0 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -16,6 +16,7 @@
    * Misc fixes and additions to dependency checks
    * Const correctness
    * cert_write with selfsign should use issuer_name as subject_name
+   * Fix ECDSA corner case: missing reduction mod N (found by DualTachyon)
 
 = PolarSSL 1.3.1 released on 2013-10-15
 Features