kiji-scoring-server: SCORSRVR-25. Bump kiji-schema version to latest 1.4.2-SNAPSHOT.

issue: https://jira.kiji.org/browse/SCORSRVR-25
review: https://review.kiji.org/r/1896
commit: https://github.com/kijiproject/kiji-scoring-server/commit/cffa502f76d45cda9a0e27c218c0e6ff955e96f9