[libmicrohttpd] Typo?: MHD_SUPPRESS_DATE_NO_CLOCK and MHD_NO_FLAG

[silvioprog]

Hello masters,

I've noticed all flags for `USE` scope was prefixed with `MHD_USE_*`, except these two flags. So, it was a typo or is that OK? Anyway MHD_USE_SUPPRESS_DATE and MHD_USE_NO_FLAG makes more sense, following the same other FLAGs pattern.

Thanks!

--

Silvio Clécio