Make workstation-ostree-support (AW) packages mandatory
    
    The group description says these are "mandatory", so they should
    probably be, well, mandatory. This means that compose of any
    deliverable that contains them will fail if they cannot be
    installed, as opposed to 'succeeding' but with the package
    silently left out.
    
    Signed-off-by: Adam Williamson <awilliam@redhat.com>