Wheel bundles fixes
    
    * make wheel_bundle no longer bundles ipaplatform
    * ipaclient and ipalib use a consistent extra tag for the install
      subpackage. `pip install ipalib[ipalib.install]` looks a bit silly.
    
    https://fedorahosted.org/freeipa/ticket/6474
    
    Signed-off-by: Christian Heimes <cheimes@redhat.com>
    Reviewed-By: Tomas Krizek <tkrizek@redhat.com>