Test repeated installation of the primary with DNS enabled and domain set
    
    Test that a repeated installation of the primary with DNS enabled
    will lead to a already installed message and not in "DNS zone X
    already exists in DNS" in check_zone_overlap.
    
    The error is only occuring if domain is set explicitly in the command
    line installer as check_zone_overlap is used in the domain_name validator.
    
    Reviewed-By: Christian Heimes <cheimes@redhat.com>