kiji-scoring: SCORE-143. Correct improper release retain in rereadFreshenerRecords

issue: https://jira.kiji.org/browse/SCORE-143
review: https://review.kiji.org/r/1464
commit: https://github.com/kijiproject/kiji-scoring/commit/def356774556659a916c303297ad37c15a6f8c38