[gtk] x11: Set BackPixmap = None unconditionally

[Benjamin Otte <otte src gnome org>]

commit 6afb6bb9d2c81136cddab97a541b1f8a863757da
Author: Benjamin Otte <otte redhat com>
Date:   Fri Jul 13 18:59:01 2018 +0200

    x11: Set BackPixmap = None unconditionally
    
    Makes it more obvious what we actually want.
    
    Related: #1134

 gdk/x11/gdksurface-x11.c | 12 ++----------
 1 file changed, 2 insertions(+), 10 deletions(-)
---
diff --git a/gdk/x11/gdksurface-x11.c b/gdk/x11/gdksurface-x11.c
index 0a7563efe8..f04f74d486 100644
--- a/gdk/x11/gdksurface-x11.c
+++ b/gdk/x11/gdksurface-x11.c
@@ -880,16 +880,8 @@ _gdk_x11_display_create_surface_impl (GdkDisplay    *display,
     {
       class = InputOutput;
 
-      if (gdk_display_is_rgba (display))
-        {
-          xattributes.background_pixel = 0;
-          xattributes_mask |= CWBackPixel;
-        }
-      else
-        {
-          xattributes.background_pixmap = None;
-          xattributes_mask |= CWBackPixmap;
-        }
+      xattributes.background_pixmap = None;
+      xattributes_mask |= CWBackPixmap;
 
       xattributes.border_pixel = BlackPixel (xdisplay, x11_screen->screen_num);
       xattributes_mask |= CWBorderPixel;