Remove erlang_template_helper. It's only used one in the Riak
role, and for that instance I replaced it with a literal.
Bump Riak cookbook to 2.3.0 and Riak CS cookbook to 2.1.0.
Fix for the Riak backend for CS startup error.
Merge pull request #26 from basho/hc-fix-riak-cs-backend

Fix Riak startup error due to missing `riak_cs_kv_multi_backend`.