idviews: Display the list of hosts when using --all
    
    Enumerating hosts is a potentially expensive operation (uses paged
    search to list all the hosts the ID view applies to). Show the list
    of the hosts only if explicitly asked for (or asked for --all).
    Do not display with --raw, since this attribute does not exist in
    LDAP.
    
    Part of: https://fedorahosted.org/freeipa/ticket/3979
    
    Reviewed-By: Petr Viktorin <pviktori@redhat.com>
    Reviewed-By: Petr Vobornik <pvoborni@redhat.com>
    Reviewed-By: Alexander Bokovoy <abokovoy@redhat.com>