Fix non compliance SSLv3 in server extension handling.

The server code parses the client hello extensions even when the
protocol is SSLv3 and this behaviour is non compliant with rfc6101.
Also the server sends extensions in the server hello and omitting
them may prevent interoperability problems.
diff --git a/ChangeLog b/ChangeLog
index 3b32873..986eabd 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -26,6 +26,7 @@
    * Fix issue that caused a crash if invalid curves were passed to
      mbedtls_ssl_conf_curves. #373
    * Fix issue in ssl_fork_server which was preventing it from functioning. #429
+   * Fix non compliance SSLv3 in server extension handling.
 
 Changes
    * On ARM platforms, when compiling with -O0 with GCC, Clang or armcc5,