Changes with nginx 1.4.5 11 Feb 2014

    *) Bugfix: the $ssl_session_id variable contained full session
       serialized instead of just a session id.
       Thanks to Ivan Ristić.

    *) Bugfix: client connections might be immediately closed if deferred
       accept was used; the bug had appeared in 1.3.15.

    *) Bugfix: alerts "zero size buf in output" might appear in logs while
       proxying; the bug had appeared in 1.3.9.

    *) Bugfix: a segmentation fault might occur in a worker process if the
       ngx_http_spdy_module was used.

    *) Bugfix: proxied WebSocket connections might hang right after
       handshake if the select, poll, or /dev/poll methods were used.

    *) Bugfix: a timeout might occur while reading client request body in an
       SSL connection using chunked transfer encoding.

    *) Bugfix: memory leak in nginx/Windows.