Add validations for config variables.
Add validations for config variables.

treydock/graylog2-puppet,Jimdo/graylog2-puppet,Jimdo/graylog2-puppet,treydock/graylog2-puppet,Jimdo/graylog2-puppet,Graylog2/graylog2-puppet,Graylog2/graylog2-puppet,Graylog2/graylog2-puppet,treydock/graylog2-puppet