Changes with nginx 1.7.6 30 Sep 2014
*) Change: the deprecated "limit_zone" directive is not supported anymore.
*) Feature: the "limit_conn_zone" and "limit_req_zone" directives now can be used with combinations of multiple variables.
*) Bugfix: request body might be transmitted incorrectly when retrying a FastCGI request to the next upstream server.
*) Bugfix: in logging to syslog.