[clutter/clutter-1.18] stage-cogl: Fix feature check in clutter_stage_cogl_redraw

[Adel Gadllah <agadllah src gnome org>]

commit 06387c3fd79f174be3a8c12afda27b523e696153
Author: Adel Gadllah <adel gadllah gmail com>
Date:   Fri Mar 14 10:41:57 2014 +0100

    stage-cogl: Fix feature check in clutter_stage_cogl_redraw
    
    We do not strictly require the 'swap-region' Cogl feature in order to use
    clipped redraws: they work equally well with just the 'buffer-age' Cogl
    feature.
    
    https://bugzilla.gnome.org/show_bug.cgi?id=726313

 clutter/cogl/clutter-stage-cogl.c |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)
---
diff --git a/clutter/cogl/clutter-stage-cogl.c b/clutter/cogl/clutter-stage-cogl.c
index ab34200..85d047c 100644
--- a/clutter/cogl/clutter-stage-cogl.c
+++ b/clutter/cogl/clutter-stage-cogl.c
@@ -448,7 +448,7 @@ clutter_stage_cogl_redraw (ClutterStageWindow *stage_window)
 
   may_use_clipped_redraw = FALSE;
   if (_clutter_stage_window_can_clip_redraws (stage_window) &&
-      can_blit_sub_buffer &&
+      (can_blit_sub_buffer || has_buffer_age) &&
       have_clip &&
       /* some drivers struggle to get going and produce some junk
        * frames when starting up... */