debian/copyright: Changed FSF's address to the new one.

debian/copyright

@@ -20,8 +20,8 @@ License:
 
    You should have received a copy of the GNU General Public License
    along with this package; if not, write to the Free Software
-   Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA
-   02111-1307, USA.
+   Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
+   02110-1301, USA.
 
 On Debian GNU/Linux systems, the complete text of the GNU General
 Public License can be found in `/usr/share/common-licenses/GPL'.