DEBUG: stream: Fix stream trace message to print response buffer state

Channels buffer state is displayed in the strem trace messages. However,
because of a typo, the request buffer was used instead of the response one.

This patch should be backported as far as 2.2.

(cherry picked from commit 5ce1299c643543c9b17b4124b299feb3caf63d9e)
Signed-off-by: Christopher Faulet <cfaulet@haproxy.com>
(cherry picked from commit 7fe753c85a99c1791f7d0df55df4b55c93dc66fb)
Signed-off-by: Christopher Faulet <cfaulet@haproxy.com>
diff --git a/src/stream.c b/src/stream.c
index 93586af..ffed2b7 100644
--- a/src/stream.c
+++ b/src/stream.c
@@ -250,8 +250,8 @@
 		chunk_appendf(&trace_buf, " buf=(%u@%p+%u/%u, %u@%p+%u/%u)",
 			      (unsigned int)b_data(&req->buf), b_orig(&req->buf),
 			      (unsigned int)b_head_ofs(&req->buf), (unsigned int)b_size(&req->buf),
-			      (unsigned int)b_data(&req->buf), b_orig(&req->buf),
-			      (unsigned int)b_head_ofs(&req->buf), (unsigned int)b_size(&req->buf));
+			      (unsigned int)b_data(&res->buf), b_orig(&res->buf),
+			      (unsigned int)b_head_ofs(&res->buf), (unsigned int)b_size(&res->buf));
 	}
 
 	/* If msg defined, display htx info if defined (level > USER) */