Remove meta_window_new_with_attrs

The compositor code used to handle X windows that didn't have a
corresponding MetaWindow (see commit d538690b), which is why the
attribute query is separated.

As that doesn't happen any more, we can clean up. No functional changes.

Suggested by Owen Taylor.

https://bugzilla.gnome.org/show_bug.cgi?id=721345

src/core/window-private.h

@@ -484,12 +484,8 @@ struct _MetaWindowClass
 
 MetaWindow* meta_window_new                (MetaDisplay *display,
                                             Window       xwindow,
-                                            gboolean     must_be_viewable);
-MetaWindow* meta_window_new_with_attrs     (MetaDisplay       *display,
-                                            Window             xwindow,
-                                            gboolean           must_be_viewable,
-                                            MetaCompEffect     effect,
-                                            XWindowAttributes *attrs);
+                                            gboolean     must_be_viewable,
+                                            MetaCompEffect     effect);
 void        meta_window_unmanage           (MetaWindow  *window,
                                             guint32      timestamp);
 void        meta_window_calc_showing       (MetaWindow  *window);