* stop sending the content for head requests, even when its supplied by the

* stop sending the content for head requests, even when its supplied by the
  fcgi. Required by RFC 7231 and RFC 3875 section 4.3.2.
* If the client sends an empty body without a Content-Lenght:
  do not add the Content-Lenght if it's a HEAD request.
  If it's a HEAD request, the Content-Lenght should show the size of the
  equivalent GET request, but we don't know how much that will be so
  don't lie.

found by and fix suggested by Ross L Richardson, Thanks!

Additionally:

* when the fcgi supplies a Content-Length header, do not remove it and
  set Transfer-Encoding: chunked. Instead, leave the Content-Lenght
  header in place, as obviously the fcgi knows how much data will come.

ok claudio@