Ticket 50317 - fix ds-backtrace issue on latest gdb
    
    Bug Description: ds-backtrace was failing due to a
    type issue on latest python/gdb on suse.
    
    Fix Description: If debug info is missing, a nonetype
    was returned in the backtrace, causing a type mismatch
    on " ".join().
    
    https://pagure.io/389-ds-base/pull-request/50317
    
    Author: William Brown <william@blackhats.net.au>
    
    Review by: ???