BUG/MINOR: compression/htx: Don't compress responses with unknown body length

In HTX, if the body length of a response cannot be determined, we must not try
to compress it.
diff --git a/src/flt_http_comp.c b/src/flt_http_comp.c
index ddcdce6..ce0dba1 100644
--- a/src/flt_http_comp.c
+++ b/src/flt_http_comp.c
@@ -914,7 +914,7 @@
 	    (txn->status != 203))
 		goto fail;
 
-	if (msg->flags & HTTP_MSGF_BODYLESS)
+	if (!(msg->flags & HTTP_MSGF_XFER_LEN) || msg->flags & HTTP_MSGF_BODYLESS)
 		goto fail;
 
 	/* content is already compressed */