dirmngr,w32: Make https with ntbtls work.
* dirmngr/http.c (simple_cookie_functions): New. (send_request) [HTTP_USE_NTBTLS, W32]: Use es_fopencookie. (cookie_read): Factor some code out to ... (read_server): new. (simple_cookie_read, simple_cookie_write) [W32]: New.
- Signed-off-by: Werner Koch <wk@gnupg.org>