Create unit tests for the f8a_worker/data_normalizer/go.py

[tisnik]

Unit tests needs to be created for the module f8a_worker/data_normalizer/go.py

[msrb]

@tisnik there are some tests here: https://github.com/fabric8-analytics/fabric8-analytics-worker/blob/master/tests/test_data_normalizer.py#L84-L118

Worker code should use normalize() function. It's like a factory which will instantiate appropriate normalizer. I.e. worker code should not use the go.py module directly.