Description:
------------
When calling php-fpm -y $configfile -t to check configuration file it reports success though php-fpm would fail to startup (or exit if sent SIGUSR2 to reload).

In fpm error log I find the following error:
[11-Dec-2014 14:34:59] NOTICE: Reloading in progress ...
[11-Dec-2014 14:34:59] NOTICE: reloading: execvp("/usr/lib/php5.5/bin/php-fpm", {"/usr/lib/php5.5/bin/php-fpm", "-y", "/etc/php/fpm-php5.5/php-fpm.conf"})
[11-Dec-2014 14:34:59] ERROR: [pool site] cannot get uid for user 'siteuser'
[11-Dec-2014 14:34:59] ERROR: FPM initialization failed

This problem case should be caught by `php-fpm -t` call.
Otherwise reloading after "successful" configuration test ends up in fpm exiting (and thus service downtime).

Test script:
---------------
in fpm.conf:

[site]
user = siteuser
group = sitegroup
listen = /path/to/unix/socket
listen.owner = siteuser
listen.group = webserver
listen.mode = 0660
...

Expected result:
----------------
`php-fpm -t` should report an issue

Actual result:
--------------
`php-fpm -t` reports success