Log Message:
Update wip/riak to 2.1.1

Riak 2.1.1

Fixes:
- Make default handoff_ip value 0.0.0.0 in vars.config.

Riak 2.1.0

New features:
- Performance Improvements
- Write-Once Bucket Type

Changes:
- Applies fix to most causes of data loss from repeated causal history.
- Update API to retrieve active preflist based on particular bucket/key.
- Add a JSON writer for several riak-admin commands
- Integrate performance patches into Erlang R16 VM used by Riak
- Add riak_core_ring_manager:is_stable_ring/0 to public API.
- Add search_query_latency_mean and search_index_latency_mean metrics.

Bugs fixed:
- Timeouts during bulk data load, possible tie in to yz_events crash and
  a bad state on core create
- Don't delete siblings in YZ when using SC or CRDTs.
- Creating a new search index via HTTP responds before the index
  is available
- AAE Failing hourly, with exit value {badarg,46},
  [{base64,decode_binary[{base64.erl…
- yz_events:handle_info called with bad arguments.
- Fix YZ stats name typo from throughput to throughput.
- SSL connections from peers with matching wildcard name are
  always rejected.