kiji-schema: SCHEMA-897. Minor error in documentation of KijiClientTest.

issue: https://jira.kiji.org/browse/SCHEMA-897
review: https://review.kiji.org/r/2090
commit: https://github.com/kijiproject/kiji-schema/commit/e4d17d8a11208c6a9f3d79c49ebe00184ae05e29