CLEANUP: mux-quic: remove useless app_ops is_active callback

Timeout in QUIC MUX has evolved from the simple first implementation. At
the beginning, a connection was considered dead unless bidirectional
streams were opened. This was abstracted through an app callback
is_active().

Now this paradigm has been reversed and a connection is considered alive
by default, unless an error has been reported or a timeout has already
been fired. The callback is_active() is thus not used anymore and can be
safely removed to simplify qcc_is_dead().

This commit should be backported to 2.6.

include/haproxy/mux_quic-t.h

@@ -176,7 +176,6 @@ struct qcc_app_ops {
 	size_t (*snd_buf)(struct stconn *sc, struct buffer *buf, size_t count, int flags);
 	void (*detach)(struct qcs *qcs);
 	int (*finalize)(void *ctx);
-	int (*is_active)(const struct qcc *qcc, void *ctx);
 	void (*release)(void *ctx);
 	void (*inc_err_cnt)(void *ctx, int err_code);
 };

src/h3.c

@@ -1192,18 +1192,6 @@ static void h3_release(void *ctx)
 	pool_free(pool_head_h3c, h3c);
 }
 
-/* Check if the H3 connection can still be considered as active.
- *
- * Return true if active else false.
- */
-static int h3_is_active(const struct qcc *qcc, void *ctx)
-{
-	if (qcc->strms[QCS_CLT_BIDI].nb_streams)
-		return 1;
-
-	return 0;
-}
-
 /* Increment the h3 error code counters for <error_code> value */
 static void h3_stats_inc_err_cnt(void *ctx, int err_code)
 {
@@ -1238,7 +1226,6 @@ const struct qcc_app_ops h3_ops = {
 	.snd_buf     = h3_snd_buf,
 	.detach      = h3_detach,
 	.finalize    = h3_finalize,
-	.is_active   = h3_is_active,
 	.release     = h3_release,
 	.inc_err_cnt = h3_stats_inc_err_cnt,
 };

src/hq_interop.c

@@ -164,16 +164,7 @@ static size_t hq_interop_snd_buf(struct stconn *sc, struct buffer *buf,
 	return total;
 }
 
-static int hq_is_active(const struct qcc *qcc, void *ctx)
-{
-	if (!eb_is_empty(&qcc->streams_by_id))
-		return 1;
-
-	return 0;
-}
-
 const struct qcc_app_ops hq_interop_ops = {
 	.decode_qcs = hq_interop_decode_qcs,
 	.snd_buf    = hq_interop_snd_buf,
-	.is_active  = hq_is_active,
 };

src/mux_quic.c

@@ -1001,10 +1001,6 @@ static void qcs_destroy(struct qcs *qcs)
 
 static inline int qcc_is_dead(const struct qcc *qcc)
 {
-	if (qcc->app_ops && qcc->app_ops->is_active &&
-	    qcc->app_ops->is_active(qcc, qcc->ctx))
-		return 0;
-
 	if ((qcc->conn->flags & CO_FL_ERROR) || !qcc->task)
 		return 1;