Crash when streaming a body back to the client.

I was attempting to stream a request back to the client with a {stream, streambody()} response. This resulted in a crash in webmachine_logger when calling integer_to_list with the atom 'chunked'.

=ERROR REPORT==== 30-Sep-2011::11:24:35 ===
** Generic server webmachine_logger terminating 
** Last message in was {'$gen_cast',
                        {log_access,
                         {wm_log_data,file_srv,
                          {1317,396275,125864},
                          'HEAD',
                          {4,
                           {"user-agent",
                            {'User-Agent',
                             "curl/7.21.4 (i386-pc-win32) libcurl/7.21.4 OpenSSL/0.9.8r zlib/1.2.5 libidn/1.18 libssh2/1.2.7 librtmp/2.3"},
                            {"host",
                             {'Host',"localhost:8000"},
                             {"accept",{'Accept',"*/*"},nil,nil},
                             nil},
                          "127.0.0.1","/files/sqlncli.msi",
                          {1,1},
                          200,chunked,
                          {1317,396275,172860},
                          {1317,396275,172861},
                          []}}}
** When Server state == {state,
                            {2011,9,30,15},
                            "priv/log/access.log",
                            {webmachine_logger,
                                "priv/log/access.log.2011_09_30_15",
                                {file_descriptor,prim_file,
                                    {#Port<0.3555>,720}}}}
** Reason for termination == 
** {badarg,[{erlang,integer_to_list,[chunked]},
            {webmachine_logger,format_req,1},
            {webmachine_logger,handle_cast,2},
            {gen_server,handle_msg,5},
            {proc_lib,init_p_do_apply,3}]}