In the case where the user asked for the usage of the setup, uninstall or upgrade CLI, we were returning an error code systematically (the error code corresponding to an error in the data provided by the user).  
With this modifications when the user asks for the usage explicitly we return an error code 0.  In addition to that, when the usage is asked explicitly in the command line  for the usage it is written to the standard output.  When we display the usage because of an error on the data provided by the user the usage is displayed in the error output.