add openssl exception to debian/copyright

debian/copyright

@@ -1,12 +1,24 @@
 Upstream Author: The Sipwise Team - http://sipwise.com
 Copyright: 2007-2013, Sipwise GmbH, Austria
-License: GPL-3+
+License: GPL-3+ with OpenSSL exception
  This program is free software; you can redistribute it
  and/or modify it under the terms of the GNU General Public
  License as published by the Free Software Foundation; either
  version 3 of the License, or (at your option) any later
  version.
  .
+ In addition, as a special exception, the author of this
+ program gives permission to link the code of its
+ release with the OpenSSL project's "OpenSSL" library (or
+ with modified versions of it that use the same license as
+ the "OpenSSL" library), and distribute the linked
+ executables. You must obey the GNU General Public
+ License in all respects for all of the code used other
+ than "OpenSSL".  If you modify this file, you may extend
+ this exception to your version of the file, but you are
+ not obligated to do so.  If you do not wish to do so,
+ delete this exception statement from your version.
+ .
  This program is distributed in the hope that it will be
  useful, but WITHOUT ANY WARRANTY; without even the implied
  warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR