Variables: honor no_cacheable for not_found variables. Variables with the "not_found" flag set follow the same rules as ones with the "valid" flag set. Make sure ngx_http_get_flushed_variable() will flush non-cacheable variables with the "not_found" flag set. This fixes at least one known problem with $args not available in a subrequest (with args) when there were no args in the main request and $args variable was queried in the main request (reported by Laurence Rowe aka elro on irc). Also this eliminates unneeded call to ngx_http_get_indexed_variable() in cacheable case (as it will return cached value anyway).

scgi_param  REQUEST_METHOD     $request_method;
scgi_param  REQUEST_URI        $request_uri;
scgi_param  QUERY_STRING       $query_string;
scgi_param  CONTENT_TYPE       $content_type;

scgi_param  DOCUMENT_URI       $document_uri;
scgi_param  DOCUMENT_ROOT      $document_root;
scgi_param  SCGI               1;
scgi_param  SERVER_PROTOCOL    $server_protocol;
scgi_param  HTTPS              $https if_not_empty;

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