PUT by s3cmd results in error with crash.log below:

```
2014-06-04 18:44:48 =ERROR REPORT====
webmachine error: path="/buckets/test/objects/rebar.config"
{error,{exit,{{badarg,[{erlang,list_to_binary,[undefined],[]},{riak_cs_put_fsm,is_digest_valid,2,[{file,"src/riak_cs_put_fsm.erl"},{line,326}]},{riak_cs_put_fsm,done,3,[{file,"src/riak_cs_put_fsm.erl"},{line,288}]},{gen_fsm,handle_msg,7,[{file,"gen_fsm.erl"},{line,494}]},{proc_lib,init_p_do_apply,3,[{file,"proc_lib.erl"},{line,227}]}]},{gen_fsm,sync_send_event,[<0.1610.0>,{finalize,undefined},infinity]}},[{gen_fsm,sync_send_event,3,[{file,"gen_fsm.erl"},{line,214}]},{riak_cs_wm_object,finalize_request,3,[{file,"src/riak_cs_wm_object.erl"},{line,443}]},{riak_cs_wm_common,accept_body,2,[{file,"src/riak_cs_wm_common.erl"},{line,342}]},{webmachine_resource,resource_call,3,[{file,"src/webmachine_resource.erl"},{line,186}]},{webmachine_resource,do,3,[{file,"src/webmachine_resource.erl"},{line,142}]},{webmachine_decision_core,resource_call,1,[{file,"src/webmachine_decision_core.erl"},{line,48}]},{webmachine_decision_core,accept_helper,1,[{file,"src/webmachine_decision_core.erl"},{line,612}]},{webmachine_decision_core,decision,1,[{file,"src/webmachine_decision_core.erl"},{line,517}]}]}}
[{gen_fsm,sync_send_event,3,[{file,"gen_fsm.erl"},{line,214}]},{riak_cs_wm_object,finalize_request,3,[{file,"src/riak_cs_wm_object.erl"},{line,443}]},{riak_cs_wm_common,accept_body,2,[{file,"src/riak_cs_wm_common.erl"},{line,342}]},{webmachine_resource,resource_call,3,[{file,"src/webmachine_resource.erl"},{line,186}]},{webmachine_resource,do,3,[{file,"src/webmachine_resource.erl"},{line,142}]},{webmachine_decision_core,resource_call,1,[{file,"src/webmachine_decision_core.erl"},{line,48}]},{webmachine_decision_core,accept_helper,1,[{file,"src/webmachine_decision_core.erl"},{line,612}]},{webmachine_decision_core,decision,1,[{file,"src/webmachine_decision_core.erl"},{line,517}]}]
```

at 1e9e0e93e20235f248568bab37279070f3161755