BUG/MEDIUM: httpclient: Don't remove HTX header blocks before duplicating them

Commit 534645d6 ("BUG/MEDIUM: httpclient: Fix loop consuming HTX blocks from
the response channel") introduced a regression. When the response is
consumed, The HTX header blocks are removed before duplicating them. Thus,
the first header block is always lost.

This patch must be backported as far as 2.5.
1 file changed