Description:
------------
Php sends 2 fastcgi FCGI_END_REQUEST records instead of one when fastcgi_finish_request(); called and fpm param max_requests exceeded.

* one is sent on fastcgi_finish_request(); call
* other is sent in block  

fpm_main.c:1951 

requests++; 
if (max_requests && (requests == max_requests)) { 
    fcgi_finish_request(&request, 1); 
    break; 
}


I have created pull request for this bug https://github.com/php/php-src/pull/709
 
It confuses fastcgi client (i.e. nginx) receiving 2 FCGI_END_REQUEST records one after another.

Test script:
---------------
<?php

ignore_user_abort();
fastcgi_finish_request();
sleep(10);

?>

Nginx configuration

upstream fpm
{
    server 127.0.0.1:9000;
    keepalive 1;
}

server
{
    ......
    fastcgi_keep_conn on;
    fastcgi_param SCRIPT_NAME /index.php;
    fastcgi_pass fpm;
    ......
}

PHP FPM configuration

max_children = 1
max_requests = 2

Expected result:
----------------
No errors in nginx error log

Actual result:
--------------
Every second request is finished with 502 status

Nginx error.log contains records:

2014/07/07 13:42:58 [error] 11253#0: *1 upstream sent unexpected FastCGI record: 3 while reading response header from upstream, client: 127.0.0.1, server: localhost, request: "GET /nginx_test.phtml HTTP/1.1", upstream: "fastcgi://127.0.0.1:8002", host: "localhost:8081"