Adjust rebar.config so that Erlang R14B04 can be used.
Adjust rebar.config so that Erlang R14B04 can be used.

Fixes: none

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