MINOR: stream: Always get idle duration from the session

Since the idle duration provided by the session is always up-to-date, there
is no more reason to rely on the multiplexer cs_info to set it to the
stream.
diff --git a/src/http_ana.c b/src/http_ana.c
index d89b7d5..6659f7e 100644
--- a/src/http_ana.c
+++ b/src/http_ana.c
@@ -109,13 +109,8 @@
 	s->srv_error = http_return_srv_error;
 
 	/* If there is data available for analysis, log the end of the idle time. */
-	if (c_data(req) && s->logs.t_idle == -1) {
-		const struct cs_info *csinfo = si_get_cs_info(objt_cs(s->si[0].end));
-
-		s->logs.t_idle = ((csinfo)
-				  ? csinfo->t_idle
-				  : tv_ms_elapsed(&s->logs.tv_accept, &now) - s->logs.t_handshake);
-	}
+	if (c_data(req) && s->logs.t_idle == -1)
+		s->logs.t_idle = sess->t_idle;
 
 	/*
 	 * Now we quickly check if we have found a full valid request.
diff --git a/src/stream.c b/src/stream.c
index 15ea23d..49654bd 100644
--- a/src/stream.c
+++ b/src/stream.c
@@ -351,14 +351,13 @@
 		s->logs.accept_date = csinfo->create_date;
 		s->logs.tv_accept = csinfo->tv_create;
 		s->logs.t_handshake = csinfo->t_handshake;
-		s->logs.t_idle = csinfo->t_idle;
 	}
 	else {
 		s->logs.accept_date = sess->accept_date;
 		s->logs.tv_accept = sess->tv_accept;
 		s->logs.t_handshake = sess->t_handshake;
-		s->logs.t_idle = -1;
 	}
+	s->logs.t_idle = sess->t_idle;
 
 	/* default logging function */
 	s->do_log = strm_log;