Perl: disabled not_modified filter (ticket #1786). Embedded perl does not set any request fields needed for conditional requests processing. Further, filter finalization in the not_modified filter can cause segmentation faults due to cleared ctx as in ticket #1786. Before 5fb1e57c758a (1.7.3) the not_modified filter was implicitly disabled for perl responses, as r->headers_out.last_modified_time was -1. This change restores this behaviour by using the explicit r->disable_not_modified flag. Note that this patch doesn't try to address perl module robustness against filter finalization and other errors returned from filter chains. It should be eventually reworked to handle errors instead of ignoring them.

uwsgi_param  QUERY_STRING       $query_string;
uwsgi_param  REQUEST_METHOD     $request_method;
uwsgi_param  CONTENT_TYPE       $content_type;
uwsgi_param  CONTENT_LENGTH     $content_length;

uwsgi_param  REQUEST_URI        $request_uri;
uwsgi_param  PATH_INFO          $document_uri;
uwsgi_param  DOCUMENT_ROOT      $document_root;
uwsgi_param  SERVER_PROTOCOL    $server_protocol;
uwsgi_param  REQUEST_SCHEME     $scheme;
uwsgi_param  HTTPS              $https if_not_empty;

uwsgi_param  REMOTE_ADDR        $remote_addr;
uwsgi_param  REMOTE_PORT        $remote_port;
uwsgi_param  SERVER_PORT        $server_port;
uwsgi_param  SERVER_NAME        $server_name;