BUG/MINOR: quic: Really cancel the connection timer from qc_set_timer()

The ->expire field of the timer task to be cancelled was not reset
to TICK_ETERNITY.

Must be backported to 2.6 and 2.7.
diff --git a/src/quic_conn.c b/src/quic_conn.c
index 503e7bb..419d1c6 100644
--- a/src/quic_conn.c
+++ b/src/quic_conn.c
@@ -782,8 +782,11 @@
 	if (tick_isset(pto))
 		qc->timer = pto;
  out:
-	if (qc->timer_task && qc->timer != TICK_ETERNITY) {
-		if (tick_is_expired(qc->timer, now_ms)) {
+	if (qc->timer_task) {
+		if (qc->timer == TICK_ETERNITY) {
+			qc->timer_task->expire = TICK_ETERNITY;
+		}
+		else  if (tick_is_expired(qc->timer, now_ms)) {
 			TRACE_DEVEL("wakeup asap timer task", QUIC_EV_CONN_STIMER, qc);
 			task_wakeup(qc->timer_task, TASK_WOKEN_MSG);
 		}