The 'dst' optionnal field on a httpclient request can be used to set an
alternative server address in the haproxy address format. Which means it
could be use with unix@, ipv6@ etc.
Should fix issue #1471.
This patch allows to replace the host header generated by the
httpclient instead of adding a new one, resulting in the server replying
an error 400.
The host header is now generated from the uri only if it wasn't found in
the list of headers.
Also add a new request in the VTC file to test this.
This patch must be backported in 2.5.
Improve the httpclient reg-tests to test the streaming,
The regtest now sends a big payload to vtest, then receive a payload
from vtest and send it again.
This reg-test is heavily inspired by the lua_socket.vtc one.
It replaces the HTTP/1.1 request made manually with a socket object with
an httpclient object.
