Changes with nginx 1.7.1 27 May 2014
*) Feature: the "$upstream_cookie_..." variables.
*) Feature: the $ssl_client_fingerprint variable.
*) Feature: the "error_log" and "access_log" directives now support logging to syslog.
*) Feature: the mail proxy now logs client port on connect.
*) Bugfix: memory leak if the "ssl_stapling" directive was used. Thanks to Filipe da Silva.
*) Bugfix: the "alias" directive used inside a location given by a regular expression worked incorrectly if the "if" or "limit_except" directives were used.
*) Bugfix: the "charset" directive did not set a charset to encoded backend responses.
*) Bugfix: a "proxy_pass" directive without URI part might use original request after the $args variable was set. Thanks to Yichun Zhang.
*) Bugfix: in the "none" parameter in the "smtp_auth" directive; the bug had appeared in 1.5.6. Thanks to Svyatoslav Nikolsky.
*) Bugfix: if sub_filter and SSI were used together, then responses might be transferred incorrectly.
*) Bugfix: nginx could not be built with the --with-file-aio option on Linux/aarch64.