remove unused library from unit tests
remove unused library from unit tests

rifung/gcp-service-broker,joshlong/gcp-service-broker,rifung/gcp-service-broker,GoogleCloudPlatform/gcp-service-broker,joshlong/gcp-service-broker,rifung/gcp-service-broker,rifung/gcp-service-broker,GoogleCloudPlatform/gcp-service-broker