[libhandy] preferences-window: Fix setting the page's vertical adjustment

[Alexander Mikhaylenko <alexm src gnome org>]

commit c254d757f8f8fc73306433e148ee6d3a6cb3877a
Author: Adrien Plazas <kekun plazas laposte net>
Date:   Wed Jun 3 21:38:26 2020 +0200

    preferences-window: Fix setting the page's vertical adjustment
    
    This accesses a page's vertical adjustment rather than using the page as
    if it was a scrolled window, which is incorrect as we made
    HdyPreferencesPage inherit from GtkBin instead of GtkScrolledWindow.
    This fixes a crash when activating a row.

 src/hdy-preferences-window.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)
---
diff --git a/src/hdy-preferences-window.c b/src/hdy-preferences-window.c
index 9569eeea..34521ddf 100644
--- a/src/hdy-preferences-window.c
+++ b/src/hdy-preferences-window.c
@@ -176,7 +176,7 @@ search_result_activated_cb (HdyPreferencesWindow *self,
   g_assert (page != NULL);
   g_assert (row != NULL);
 
-  adjustment = gtk_scrolled_window_get_vadjustment (GTK_SCROLLED_WINDOW (page));
+  adjustment = hdy_preferences_page_get_vadjustment (page);
 
   g_assert (adjustment != NULL);