Set servers list as default facet in topology facet group
    
    Since there is a new warning about only one CA server, the default facet
    of topology facet group is set to servers list where the warning is.
    So the warning will be shown right after clicking on Topology section.
    
    Part of: https://fedorahosted.org/freeipa/ticket/5828
    
    Reviewed-By: Tomas Krizek <tkrizek@redhat.com>