ipa-cert-fix: use timezone-aware datetime
    
    ipa-cert-fix compares the current datetime with the
    value obtained from a cert.not_valid_after.
    With the fix for #9425, not_valid_after is timezone
    aware and cannot be compared to a naive datetime.
    
    Make the datetime "now" timezone aware.
    Related: https://pagure.io/freeipa/issue/9425
    
    Signed-off-by: Florence Blanc-Renaud <flo@redhat.com>
    Reviewed-By: Alexander Bokovoy <abokovoy@redhat.com>