Incorrect namespace created

[magick93]

Steps to reproduce

1. Add def envStage = utils.environmentNamespace('my-project') to a Jenkinsfile
2. Run in Jenkins

Expected

We would expect a new namespace of 'my-project' is created.

Actual 'default-my-project' is created.

[nickdgriffin]

I don't think that's the purpose of that function: https://github.com/fabric8io/fabric8-pipeline-library/blob/master/src/io/fabric8/Utils.groovy#L20