Fixed unrealize handler to comply with the documentation (which mentions

Fixed unrealize handler to comply with the documentation (which mentions

2018-02-11  Federico Mena Quintero  <federico@nuclecu.unam.mx>

	* gtk/gtkclist.c:
	* gtk/gtkentry.c:
	* gtk/gtkfixed.c:
	* gtk/gtkhandlebox.c:
	* gtk/gtknotebook.c:
	* gtk/gtkpaned.c:
	* gtk/gtkpreview.c:
	* gtk/gtkrange.c:
	* gtk/gtkruler.c:
	* gtk/gtktext.c:
	* gtk/gtkviewport.c:
	Fixed unrealize handler to comply with the
	documentation (which mentions the right thing to do).