kiji-schema: SCHEMA-654. Improve tools for testing ZooKeeper interactions

issue: https://jira.kiji.org/browse/SCHEMA-654
review: https://review.kiji.org/r/1642
commit: https://github.com/kijiproject/kiji-schema/commit/18d0a27f6f09a072014543d3c8a2fb205dfac8c1