Back port fix for hashtree_pid not returning {error, wrong_node}  if it is no longer primary for that node from 2.1 branch.  - See https://github.com/basho/riak_kv/pull/1106
Back port fix for hashtree_pid not returning {error, wrong_node} 
if it is no longer primary for that node from 2.1 branch. 
- See https://github.com/basho/riak_kv/pull/1106
andytill/riak_kv