[metacity] stack: fix copy/paste error

[Alberts Muktupāvels <muktupavels src gnome org>]

commit c55e857351285c5f035e7ddc8539c9028596bfa3
Author: Alberts Muktupāvels <alberts muktupavels gmail com>
Date:   Sun Jul 2 16:13:19 2017 +0300

    stack: fix copy/paste error

 src/core/stack.c |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)
---
diff --git a/src/core/stack.c b/src/core/stack.c
index 8baa385..6e03952 100644
--- a/src/core/stack.c
+++ b/src/core/stack.c
@@ -1026,7 +1026,7 @@ stack_sync_to_xserver (MetaStack *stack)
       meta_topic (META_DEBUG_STACK, "%u:%d - %s ",
                   w->layer, w->stack_position, w->desc);
 
-      g_array_prepend_val (stacked, w->xwindow);
+      g_array_append_val (stacked, w->xwindow);
 
       if (w->frame)
         g_array_append_val (root_children_stacked, w->frame->xwindow);