Don't explicitly set the size of the MutterWindow texture

Setting the size of the texture causes the minimum and preferred width and
height values to be fixed at the set value. The normal requisition functions
of ClutterTexture will already report the size of the texture pixmap as the
natural size, but also allow scaling down as needed if less space is
available. We don't need that here, but we want to allow someone to make
a ClutterClone of the texture actor.

src/compositor/mutter-window.c

@@ -1512,8 +1512,6 @@ check_needs_repair (MutterWindow *self)
                     "pixmap-height", &pxm_height,
                     NULL);
 
-      clutter_actor_set_size (priv->actor, pxm_width, pxm_height);
-
       if (priv->shadow)
         clutter_actor_set_size (priv->shadow, pxm_width, pxm_height);