MINOR: conn-stream: Use unsafe functions to get conn/appctx in cs_detach_endp

There is no reason to rely on safe functions here. This patch should fix the
issue #1656.
diff --git a/src/conn_stream.c b/src/conn_stream.c
index 7adf04b..2a3ff56 100644
--- a/src/conn_stream.c
+++ b/src/conn_stream.c
@@ -350,7 +350,7 @@
 		goto reset_cs;
 
 	if (cs->endp->flags & CS_EP_T_MUX) {
-		struct connection *conn = cs_conn(cs);
+		struct connection *conn = __cs_conn(cs);
 
 		if (conn->mux) {
 			/* TODO: handle unsubscribe for healthchecks too */
@@ -372,7 +372,7 @@
 		}
 	}
 	else if (cs->endp->flags & CS_EP_T_APPLET) {
-		struct appctx *appctx = cs_appctx(cs);
+		struct appctx *appctx = __cs_appctx(cs);
 
 		cs->endp->flags |= CS_EP_ORPHAN;
 		cs_applet_release(cs);