On dev-support, service creation and ranger-kafka-plugin setup are failed

There are 2 bugs in dev-support.

1. create-ranger-services.py

"service_not_exists" returns 0 even though there is no service.

2. ranger-kafka-setup.sh

"authorizer.class.name=org.apache.ranger.authorization.kafka.authorizer.RangerKafkaAuthorizer" should be appended after a newline.
If not, kafka fails to start with wrong configuration.

PR: https://github.com/apache/ranger/pull/170/files