Remove named_validate_dnssec update step
    
    The upgrade step used to add "dnssec-validation no" to named.conf IFF
    named.conf did not contain "dnssec-validation" option at all. The
    option has been moved to 'ipa-options-ext.conf' in IPA 4.8.7. The function
    only removes the upgrade state.
    
    Signed-off-by: Christian Heimes <cheimes@redhat.com>
    Reviewed-By: Alexander Bokovoy <abokovoy@redhat.com>