[gimp/gimp-2-10] app: small fix to last commit

[Ell <ell src gnome org>]

commit 7fa5fbab94b958552b108992ad5df1663976afc6
Author: Ell <ell_se yahoo com>
Date:   Fri Jan 4 15:30:25 2019 -0500

    app: small fix to last commit
    
    (cherry picked from commit d39ac2a3f0a4ad57b07e05f0fc163293f030a365)

 app/widgets/gimphistogrameditor.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)
---
diff --git a/app/widgets/gimphistogrameditor.c b/app/widgets/gimphistogrameditor.c
index 4a249f9ff1..9c679348d8 100644
--- a/app/widgets/gimphistogrameditor.c
+++ b/app/widgets/gimphistogrameditor.c
@@ -481,7 +481,7 @@ gimp_histogram_editor_calculate_async_callback (GimpAsync           *async,
 
   editor->bg_pending = FALSE;
 
-  if (update_pending)
+  if (editor->update_pending)
     gimp_histogram_editor_update (editor);
 }