Changes with nginx 0.8.53 18 Oct 2010
*) Feature: now the "error_page" directive allows to change a status code in a redirect.
*) Feature: the "gzip_disable" directive supports special "degradation" mask.
*) Bugfix: a socket leak might occurred if file AIO was used. Thanks to Maxim Dounin.
*) Bugfix: if the first server had no "listen" directive and there was no explicit default server, then a next server with a "listen" directive became the default server; the bug had appeared in 0.8.21.