[gtk+] scrolledwindow: Avoid usage of uninitialized local

[Timm Bäder <baedert src gnome org>]

commit ed245b42cb29244f7abec9e9ea16ac34315b03b5
Author: Timm Bäder <mail baedert org>
Date:   Sat Feb 18 10:43:14 2017 +0100

    scrolledwindow: Avoid usage of uninitialized local
    
    the scrollbar passed in better be either priv->hscrollbar or
    priv->vscrollbar. Ensure that by using a simple else instead of an
    else-if and a g_assert.

 gtk/gtkscrolledwindow.c |    4 +++-
 1 files changed, 3 insertions(+), 1 deletions(-)
---
diff --git a/gtk/gtkscrolledwindow.c b/gtk/gtkscrolledwindow.c
index bc23a13..d2c3cbf 100644
--- a/gtk/gtkscrolledwindow.c
+++ b/gtk/gtkscrolledwindow.c
@@ -3188,8 +3188,10 @@ gtk_scrolled_window_allocate_scrollbar (GtkScrolledWindow *scrolled_window,
       child_allocation.width = content_allocation.width;
       child_allocation.height = sb_height;
     }
-  else if (scrollbar == priv->vscrollbar)
+  else
     {
+      g_assert (scrollbar == priv->vscrollbar);
+
       if ((_gtk_widget_get_direction (widget) == GTK_TEXT_DIR_RTL &&
           (priv->window_placement == GTK_CORNER_TOP_RIGHT ||
            priv->window_placement == GTK_CORNER_BOTTOM_RIGHT)) ||