revert riak_object->riakc_obj change in riak_moss_storage
revert riak_object->riakc_obj change in riak_moss_storage

this code is MapReduce; it runs on the riak node, and should use riak_object

dragonfax/riak_cs,dragonfax/riak_cs,yangchengjian/riak_cs,basho/riak_cs,basho/riak_cs,yangchengjian/riak_cs,laurenrother/riak_cs,dragonfax/riak_cs,basho/riak_cs,yangchengjian/riak_cs,sdebnath/riak_cs,sdebnath/riak_cs,basho/riak_cs,GabrielNicolasAvellaneda/riak_cs,basho/riak_cs_lfs,laurenrother/riak_cs,yangchengjian/riak_cs,sdebnath/riak_cs,GabrielNicolasAvellaneda/riak_cs,laurenrother/riak_cs,laurenrother/riak_cs,dragonfax/riak_cs,GabrielNicolasAvellaneda/riak_cs,basho/riak_cs_report,GabrielNicolasAvellaneda/riak_cs,sdebnath/riak_cs