[xfer] Implement xfer_vreopen() to properly handle redirections

When handling a redirection event, we need to close the existing
connection before opening the new connection.

src/net/tcp/iscsi.c

@@ -1514,7 +1514,7 @@ static int iscsi_vredirect ( struct xfer_interface *socket, int type,
 		va_end ( tmp );
 	}
 
-	return xfer_vopen ( socket, type, args );
+	return xfer_vreopen ( socket, type, args );
 }