fix used constant in send_param_adapter(), actually cosmetics only
fix used constant in send_param_adapter(), actually cosmetics only

maru/libmicrohttpd-http2,maru/libmicrohttpd-http2,ghaderer/libmicrohttpd,ghaderer/libmicrohttpd,maru/libmicrohttpd-http2,ghaderer/libmicrohttpd