Small cleanup in zone class

pcbnew/class_zone.cpp

@@ -956,13 +956,7 @@ void ZONE_CONTAINER::AddPolygon( std::vector< wxPoint >& aPolygon )
 
     outline.SetClosed( true );
 
-    // Add the outline as a new polygon in the polygon set
-    if( m_Poly->OutlineCount() == 0 )
-        m_Poly->AddOutline( outline );
-    else
-        m_Poly->AddHole( outline );
-
-    SetNeedRefill( true );
+    AddPolygon( outline );
 }