BUG/MINOR: mux-h2: fix the "show fd" dest buffer for the subscriber

Commit 98e40b981 ("MINOR: mux-h2: make the "show fd" helper also decode
the h2s subscriber when known") improved the output of "show fd" for the
H2 mux, but the output is sent to the trash buffer instead of the msg
argument. It turns out that this has no effect right now as the caller
passes the trash but this is risky.

This should be backported to 2.4.

(cherry picked from commit ba7657ca0f2a15f9bb988bc05821d088f2f05947)
Signed-off-by: Willy Tarreau <w@1wt.eu>
(cherry picked from commit 671bfab6fdb858ea712be17784e72310dbbef549)
Signed-off-by: Christopher Faulet <cfaulet@haproxy.com>
(cherry picked from commit 552426d84620e5f8d7a85a49fd2408a59301dd35)
Signed-off-by: Christopher Faulet <cfaulet@haproxy.com>
1 file changed