- While negotiating auth during PUT/POST if a user-specified
Content-Length header is set send 'Content-Length: 0'.
This is what we do already in HTTPREQ_POST_FORM and what we did in the
HTTPREQ_POST case (regression since afd288b).
Prior to this change no Content-Length header would be sent in such a
case.
Bug: https://curl.haxx.se/mail/lib-2017-02/0006.html
Reported-by: Dominik Hölzl
Closes https://github.com/curl/curl/pull/1242
