Up default server DHM size to 2048 bits

ChangeLog

diff --git a/ChangeLog b/ChangeLog
index 45c26e8..5e6932c 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -5,6 +5,9 @@
 Security
    * Increase the minimum size of Diffie-Hellman parameters accepted by the
      client to 1024 bits, to protect against Logjam attack.
+   * Increase the size of default Diffie-Hellman parameters on the server to
+     2048 bits. This can be changed with ssl_set_dh_params().
+
 
 Bugfix
    * Fix thread-safety issue in SSL debug module (found by Edwin van Vliet).