gtk2: Use gtk_widget_get_window instead of accessing the struct.
* gtk+-2/pinentry-gtk-2.c (make_transient): Don't directly access the window field of WIN. Use gtk_widget_get_window instead. (grab_keyboard): Likewise. (ungrab_keyboard): Likewise.
Patch-by: Dimitri John Ledkov <dimitri.j.ledkov@intel.com>.