[gimp] app: fix type warning.

[Jehan <jehanp src gnome org>]

commit 182786b4fbfe6ead1cd146a4261487f829d144b2
Author: Jehan <jehan girinstud io>
Date:   Wed Dec 19 16:01:06 2018 +0100

    app: fix type warning.
    
    I missed this warning when reviewing commit a9a979b2d0.
    My bad!

 app/display/gimpstatusbar.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)
---
diff --git a/app/display/gimpstatusbar.c b/app/display/gimpstatusbar.c
index 1dedf5788c..398b99881a 100644
--- a/app/display/gimpstatusbar.c
+++ b/app/display/gimpstatusbar.c
@@ -223,7 +223,7 @@ gimp_statusbar_init (GimpStatusbar *statusbar)
   store = gimp_unit_store_new (2);
   statusbar->unit_combo = gimp_unit_combo_box_new_with_model (store);
   g_object_unref (store);
-  gtk_combo_box_set_wrap_width (statusbar->unit_combo, 1);
+  gtk_combo_box_set_wrap_width (GTK_COMBO_BOX (statusbar->unit_combo), 1);
 
   gtk_widget_set_can_focus (statusbar->unit_combo, FALSE);
   g_object_set (statusbar->unit_combo, "focus-on-click", FALSE, NULL);