BUG/MEDIUM: mux-h1: Don't set CO_SFL_MSG_MORE flag on last fast-forward send

In the mux-to-mux fast-forwarding, when end-of-input is reached on the producer
side, the consumer side must not set the CO_SFL_MSG_MORE flag on send. It means
the H1C_F_CO_MSG_MORE flag must be removed from the H1 connection.

No backport needed.

src/mux_h1.c

@@ -4516,6 +4516,9 @@ static size_t h1_done_ff(struct stconn *sc)
 		sd->iobuf.offset = 0;
 		sd->iobuf.data = 0;
 
+		if (sd->iobuf.flags & IOBUF_FL_EOI)
+			h1c->flags &= ~H1C_F_CO_MSG_MORE;
+
 		/* Perform a synchronous send but in all cases, consider
 		 * everything was already sent from the SC point of view.
 		 */