when ngx_http_fastcgi_module (and memcached and proxy) call
ngx_http_upstream_add(), they set the 3rd arg, the flags argument is set
this causes specifying any optional args in upstream server directives
fail with an invalid configuration message.
is this correct behavior, and what would be the effects of setting this
flag to match the available parameters such as are set in the call to
ngx_http_upstream_add in ngx_http_uptream.c:ngx_http_upstream() ?