kiji-schema: SCHEMA-909. kiji-schema-cassandra POM lists surefire plugin twice

issue: https://jira.kiji.org/browse/SCHEMA-909
review: https://review.kiji.org/r/2110
commit: https://github.com/kijiproject/kiji-schema/commit/b8a0d910d7e958954f2c26d8f73348f8ebd57512