Remove name reference to access archiver processes

Original issue: #746

To complete multiple archiver processes support introduced at:
  #717 Only a single access archiver can run at a time
  https://github.com/basho/riak_cs/pull/717
registered name references should be removed.
Add riak_test module for access statistics
Merge pull request #747 from basho/bugfix/access-archiver-crash

Remove name reference to access archiver processes