kiji-schema: SCHEMA-363. Fix KijiDataRequestBuilder PageSize error message

issue: https://jira.kiji.org/browse/SCHEMA-363
review: https://review.kiji.org/r/1581
commit: https://github.com/kijiproject/kiji-schema/commit/7fbb28deb43acea8eb1ec8a78e811d3587b7a8c2