Build: support --enable-silent-rules for Python packages
    
    Setuptools will print only warnings. The option has to be used before
    setuptools command specification, otherwise it will not apply to sub-commands.
    
    https://fedorahosted.org/freeipa/ticket/6418
    
    Reviewed-By: Lukas Slebodnik <lslebodn@redhat.com>
    Reviewed-By: Christian Heimes <cheimes@redhat.com>