Ticket 49273 - crash when DBVERSIOn is corrupt.
    
    Bug Description:  During a disk full DBVERSIOn was corrupted.
    AS a result, we would segfault.
    
    Fix Description:  Rather than segfaulting, we should handle the
    error gracefully, with steps to resolve.
    
    https://pagure.io/389-ds-base/issue/49273
    
    Author: wibrown
    
    Review by: nhosoi (Thank you very much!)