dirmngr: Fix API difference for Windows.
* dirmngr/http.c (read_server, write_server): Use assuan_fd_t. (http_wait_response): Use FD2INT to get unsigned integer fd. (read_server, write_server): Likewise. (simple_cookie_read, simple_cookie_write): Use assuan_fd_t.
- Signed-off-by: NIIBE Yutaka <gniibe@fsij.org>