[gtk+] notebook: fix a GCC warning

[Cosimo Cecchi <cosimoc src gnome org>]

commit 897126ae2bf1d82074321e42c20b1289a348fbcb
Author: Cosimo Cecchi <cosimoc gnome org>
Date:   Wed Jan 13 08:30:02 2016 -0800

    notebook: fix a GCC warning

 gtk/gtknotebook.c |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)
---
diff --git a/gtk/gtknotebook.c b/gtk/gtknotebook.c
index 68b8230..6f61384 100644
--- a/gtk/gtknotebook.c
+++ b/gtk/gtknotebook.c
@@ -2324,7 +2324,7 @@ gtk_notebook_measure_tabs (GtkCssGadget   *gadget,
 {
   GtkWidget *widget = gtk_css_gadget_get_owner (gadget);
   GtkNotebook *notebook = GTK_NOTEBOOK (widget);
-  GtkRequisition tabs_requisition;
+  GtkRequisition tabs_requisition = { 0 };
 
   gtk_notebook_get_preferred_tabs_size (notebook, &tabs_requisition);
   if (orientation == GTK_ORIENTATION_HORIZONTAL)