package/libmicrohttpd: minor fixes and additions

Correcting the indentation inside Config.in. Also adding the missed
license information.

Note: libmicrohttpd is partialy dual licensed, if you don't need or want
to use the HTTPS option you can choose between LPGLv2.1+ and the eCos
license (http://ecos.sourceware.org/license-overview.html

).
If you use the HTTPS option you have to agree to the LGPLv2.1+!

Signed-off-by: Carsten Schoenert <c.schoenert@gmail.com>
Signed-off-by: Peter Korsgaard <jacmet@sunsite.dk>