BUG/MEDIUM: stconn: Report read activity when a stream is attached to front SC

It only concerns the front SC. But it is important to report a read activity
when a stream is created and attached to the front SC, especially in TCP. In
HTTP, when this happens, the request was necessarily received. But in TCP,
the client may open a connection without sending anything. We must still
report a first read activity in this case to be able to properly report
client timeout.

This patch must be backported to 2.8.

(cherry picked from commit 34645a6365827f1cd3929afe8c8e7055fa4556ee)
Signed-off-by: Christopher Faulet <cfaulet@haproxy.com>
diff --git a/src/stconn.c b/src/stconn.c
index 643d78e..ee9f7b9 100644
--- a/src/stconn.c
+++ b/src/stconn.c
@@ -322,6 +322,7 @@
 {
 	sc->app = &strm->obj_type;
 	sc_ep_clr(sc, SE_FL_ORPHAN);
+	sc_ep_report_read_activity(sc);
 	if (sc_ep_test(sc, SE_FL_T_MUX)) {
 		sc->wait_event.tasklet = tasklet_new();
 		if (!sc->wait_event.tasklet)