BUG/MEDIUM: mux-h2: erase h2c->wait_event.tasklet on error path

On the allocation error path in h2_init() we may check if
h2c->wait_event.tasklet needs to be released but it has not yet been
zeroed. Let's do this before jumping to the freeing location.

This needs to be backported to all maintained versions.

(cherry picked from commit 389ab0d4b4031c1a7f05fe1b4607f31737b5b9b9)
Signed-off-by: Amaury Denoyelle <adenoyelle@haproxy.com>
(cherry picked from commit acf880bc3bca425acbcbf1bf74bb78f9d71fe7ab)
Signed-off-by: Amaury Denoyelle <adenoyelle@haproxy.com>
(cherry picked from commit e955837223d3540ac644ad114a92a76efe0e7ea9)
Signed-off-by: Christopher Faulet <cfaulet@haproxy.com>
(cherry picked from commit 70de1a9835e711b1dbc721bd96ae6c676e2c3749)
Signed-off-by: Christopher Faulet <cfaulet@haproxy.com>
diff --git a/src/mux_h2.c b/src/mux_h2.c
index 4c8f565..4d56ea6 100644
--- a/src/mux_h2.c
+++ b/src/mux_h2.c
@@ -987,6 +987,7 @@
 
 	h2c->proxy = prx;
 	h2c->task = NULL;
+	h2c->wait_event.tasklet = NULL;
 	h2c->idle_start = now_ms;
 	if (tick_isset(h2c->timeout)) {
 		t = task_new(tid_bit);