lisp/net/ntlm.el: Match Mozilla Type 1 and 3 message behavior

lisp/net/ntlm.el: Match Mozilla Type 1 and 3 message behavior

* lisp/net/ntlm.el (ntlm-build-auth-request): Only set
"negotiate domain supplied" bit when a domain is supplied.  Do
not set "negotiate workstation supplied" bit.
(ntlm-build-auth-response): Set domain to empty string by
default.  Set workstation name to "WORKSTATION".  Set flags to
logical and of Type 1 and Type 2 message flags.  Remove four
trailing 0 bytes.  Always set LM response.  Hard-code domain
offset.  Reorder buffer fields.