Verify bucket type + MR filters fix

This addition verifies the bugfix in https://github.com/basho/riak_kv/pull/888/files

Unfortunately the test is failing for unrelated reasons. See https://github.com/basho/riak_kv/issues/960. To verify this fix before a fix for riak_kv#960 is addressed, you may have to comment out the line that fails there (149).