wks: Put stdout into binary mode for Windows.

* tools/send-mail.c (send_mail_to_file): Call es_set_binary.

Without that, output to stdout via --send is mangled: The "\r\n" is
translated to "\r\r\n" which is bad because other
software (e.g. Thunderbird) translates this again to "\n\n" and thus
put all mail header liens after the first into the body.

• Signed-off-by: Werner Koch <wk@gnupg.org>