Wrong headers

[dzubchik]

Hi! We have recently megred #46, but unfortunately, it brings a bug. When we call "add" method
https://github.com/php-pm/php-pm-httpkernel/blob/master/Bridges/HttpKernel.php#L183, we add headers from React request, but we can not track headers which were added by Symfony request from ServerBag. As it uses superglobal array $_SERVER, which only grows during application lifetime. For example:
I send regular http request, after that I send ajax request, all furtherst requests will have X-Request-With: XMLHttpRequest header. My propose is to return replace method, but move authorization headers from $_SERVER to $headers.

[marcj]

How about resetting $_SERVER at the beginning of the method?

[dzubchik]

I don't think that resetting superglobal is ok. And, furthermore, Symfony ServerBag uses it to populate headers.

[marcj]

Yes, this is an issue, because $_SERVER should contain always only headers from the $request, not from the first php bootstrap. We need to reset it anyways.

[dzubchik]

This commit fixes this php-pm/php-pm@9b63b99.