MEDIUM: proto_htx: Switch to infinite forwarding if there is no data filter

MEDIUM: proto_htx: Switch to infinite forwarding if there is no data filter

Because in HTX the parsing is done by the multiplexers, there is no reason to
limit the amount of data fast-forwarded. Of course, it is only true when there
is no data filter registered on the corresponding channel. So now, we enable the
infinite forwarding when possible. However, the HTTP message state remains
HTTP_MSG_DATA. Then, when infinite forwarding is enabled, if the flag CF_SHUTR
is set, the state is switched to HTTP_MSG_DONE.