stray unicode atom causes error_log to die

Somehow error_log event handler gets sent data that causes an additional `unicode` atom from unicode:characters_to_binary, which is passed to io:put_char/3 which doesn't exist and ...boom.

[info] [<0.31993.2>] 144.76.78.196 - - GET /public/_design/glob/_list/posts/by_date?descending=true&reduce=false&limit=5&include_docs=true&format=atom 200
[info] [<0.31789.2>] 66.249.66.216 - - GET /public/_design/glob/_list/posts/by_path?key=%5B%222012%22%2C%2203%22%2C%22metakaolin_geojson_editor%22%5D&include_docs=true&path1=2012&path2=03&path3=metakaolin_geojson_editor 200

=ERROR REPORT==== 31-Oct-2013::19:48:48 ===

• • gen_event handler couch_log crashed.
  • Was installed in error_logger
  • Last event was:
    Unknown macro: {couch_info,<<"[info] [<0.31789.2>] 66.249.66.216 - - GET /public/_design/glob/_list/posts/by_path?key=%5B%222012%22%2C%2203%22%2C%22metakaolin_geojson_editor%22%5D&include_docs=true&path1=2012&path2=03&path3=metakaolin_geojson_editor 200n">>, <<"[Thu, 31 Oct 2013 19}
  • When handler state ==
    Unknown macro: {state,<0.93.0>,2,true}
  • Reason == {badarg,
    [
    Unknown macro: {io,put_chars, [<0.93.0>,unicode, <<"[Thu, 31 Oct 2013 19}

    ,
    

    Unknown macro: {couch_log,log,3, [

    Unknown macro: {file, "/home/ubuntu/bc2/dependencies/couchdb/src/couchdb/couch_log.erl"}

    ,
    

    Unknown macro: {line,208}

    ]},
    {couch_log,handle_event,2,
    [

    ,

    Unknown macro: {line,173}

    ]},
    {gen_event,server_update,4,
    [

    Unknown macro: {file,"gen_event.erl"}

    ,

    Unknown macro: {line,522}

    ]},
    {gen_event,server_notify,4,
    [

    ,

    Unknown macro: {line,504}

    ]},
    {gen_event,handle_msg,5,[

    Unknown macro: {file,"gen_event.erl"}

    ,

    Unknown macro: {line,269}

    ]},
    {proc_lib,init_p_do_apply,3,
    [

    Unknown macro: {file,"proc_lib.erl"}

    ,

    Unknown macro: {line,239}

    ]}]}

    =ERROR REPORT==== 31-Oct-2013::19:48:48 ===

    • • Generic server couch_log terminating
      • Last message in was {gen_event_EXIT,couch_log,
        {'EXIT',
        {badarg,
        [
        Unknown macro: {io,put_chars, [<0.93.0>,unicode, <<"[Thu, 31 Oct 2013 19}

        ,
        {couch_log,log,3,
        [

        Unknown macro: {file, "/home/ubuntu/bc2/dependencies/couchdb/src/couchdb/couch_log.erl"}

        ,
        

        Unknown macro: {line,208}

        ]},
        {couch_log,handle_event,2,
        [

        ,

    ]}

    ,
    {gen_event,ser