kiji-schema: SCHEMA-660. org.kiji.schema.util.DebugResourceTracker should be less noisy

issue: https://jira.kiji.org/browse/SCHEMA-660
review: https://review.kiji.org/r/1655
commit: https://github.com/kijiproject/kiji-schema/commit/611f608230de54f532c5eecdbb02d1ba1b7e7887