[gnome-panel] panel-menu-bar-object: avoid a compiler warning

[Alberts Muktupāvels <muktupavels src gnome org>]

commit 5e510612c37bfaa4aca959206ed90e6e098a904a
Author: Alberts Muktupāvels <alberts muktupavels gmail com>
Date:   Thu May 25 00:15:26 2017 +0300

    panel-menu-bar-object: avoid a compiler warning

 gnome-panel/panel-menu-bar-object.c |    4 ++++
 1 files changed, 4 insertions(+), 0 deletions(-)
---
diff --git a/gnome-panel/panel-menu-bar-object.c b/gnome-panel/panel-menu-bar-object.c
index 3b220ec..1d84edd 100644
--- a/gnome-panel/panel-menu-bar-object.c
+++ b/gnome-panel/panel-menu-bar-object.c
@@ -76,6 +76,10 @@ panel_menu_bar_object_icon_get_pixel_size (GtkIconSize size)
       return 32;
     case GTK_ICON_SIZE_LARGE_TOOLBAR:
       return 24;
+    case GTK_ICON_SIZE_SMALL_TOOLBAR:
+    case GTK_ICON_SIZE_BUTTON:
+    case GTK_ICON_SIZE_MENU:
+    case GTK_ICON_SIZE_INVALID:
     default:
       return 16;
   }