Thanks for reporting this bug and help in making Ubuntu better. Sorry for the long delay in getting an answer for this report.
According to the logs you attached the bug was caused by the upgrader not dealing well with the "noveau" open NVIDIA drivers. If this is still an issue for you please feel free to mark the status of this report as "New" again, otherwise please ignore this message.
Thanks for reporting this bug and help in making Ubuntu better. Sorry for the long delay in getting an answer for this report.
According to the logs you attached the bug was caused by the upgrader not dealing well with the "noveau" open NVIDIA drivers. If this is still an issue for you please feel free to mark the status of this report as "New" again, otherwise please ignore this message.