kiji-schema: SCHEMA-575. race condition in HBaseKijiTableWriter state transitions

issue: https://jira.kiji.org/browse/SCHEMA-575
review: https://review.kiji.org/r/1201
commit: https://github.com/kijiproject/kiji-schema/commit/4ad712e1f5dafb372226cbbd8a2e89ebb9b0dc38