Ticket #47804 - db2bak.pl error with changelogdb
    
    Bug description: Backup utility db2bak[.pl] copies not just backend
    db files but also changelog db files, which is not associated with
    the backend instance, but the backend code blindly expected it.
    
    Fix description: If the copying directory is a changelog db dir,
    skip retrieving the backend instance info and just copy the files
    underneath
    
    https://fedorahosted.org/389/ticket/47804
    
    Reviewed by rmeggins@redhat.com (Thank you, Rich!!)