Override setContents() to trigger update of borders

git-svn-id: https://svn.apache.org/repos/asf/xmlgraphics/fop/branches/FOP_0-20-0_Alt-Design@197831 13f79535-47bb-0310-9956-ffa450edef68

src/java/org/apache/fop/area/PaddingRectangle.java

 
 import java.awt.geom.Point2D;
 import java.awt.geom.Rectangle2D;
+import org.apache.fop.area.Area.AreaGeometry;
 
 /**
  * @author pbw
         return borders;
     }
 
+    public void setContents(AreaGeometry contents) {
+        super.setContents(contents);
+        borders.setContents(this);
+    }
+
     /**
      * {@inheritDoc}
      * <p>The containing <code>BorderRectangle</code> is notified of the