wayland: re-configure surface even if size matches

gdk-wayland backend would not re-configure a surface when its size and
scale match the known size and scale.

But there might be a pending xdg_surface_configure() that would revert
this change so we should re-configure even if the currently known
size/scale match, otherwise we may end up with a wrong size after the
xdg_surface_configure() is received.

Bugzilla: https://bugzilla.gnome.org/show_bug.cgi?id=758901

gdk/wayland/gdkwindow-wayland.c

@@ -698,11 +698,6 @@ gdk_wayland_window_configure (GdkWindow *window,
   GdkDisplay *display;
   GdkEvent *event;
 
-  if (window->width == width &&
-      window->height == height &&
-      impl->scale == scale)
-    return;
-
   event = gdk_event_new (GDK_CONFIGURE);
   event->configure.window = g_object_ref (window);
   event->configure.send_event = FALSE;