MEDIUM: quic: flag listener for local accept

QUIC connections are distributed accross threads by xprt-quic according
to their CIDs. As such disable the thread selection in listener_accept
for QUIC listeners.

This prevents connection from migrating to another threads after its
allocation which can results in unexpected side-effects.
diff --git a/src/proto_quic.c b/src/proto_quic.c
index 29ae209..2834845 100644
--- a/src/proto_quic.c
+++ b/src/proto_quic.c
@@ -524,6 +524,7 @@
 	MT_LIST_INIT(&listener->rx.pkts);
 	listener->rx.odcids = EB_ROOT_UNIQUE;
 	listener->rx.cids = EB_ROOT_UNIQUE;
+	listener->rx.flags |= RX_F_LOCAL_ACCEPT;
 	HA_RWLOCK_INIT(&listener->rx.cids_lock);
 	default_add_listener(proto, listener);
 }