remove references to bluemix

[rabbah]

https://github.com/apache/incubator-openwhisk-client-go/blob/df79c14dab895db6f2371fb5dbe734a4a1185ceb/whisk/client.go#L83

and in the readme file here
https://github.com/apache/incubator-openwhisk-client-go/search?q=bluemix&unscoped_q=bluemix

[drcariel]

@rabbah I see these bluemix references in cli and openwhisk repos too - should those be removed as well?

[rabbah]

yes i think we should remove them.