[BUG] http: fix http-pretend-keepalive and httpclose/tunnel mode

Since haproxy 1.4.9, combining option httpclose and option
http-pretend-keepalive can leave the connections opened until the backend
keep-alive timeout is reached, providing bad performances.
The same can occur when the proxy is in tunnel mode.

This patch ensures that the server side connection is closed after the
response and ignore http-pretend-keepalive in tunnel mode.
1 file changed