Comment 18 for bug 1009294

This bug has reappeared in the most-recent EBS backed ubuntu-xenial AMI in AWS:

while creating images, I'm running:
`sudo apt-get -y upgrade`

to which I get prompted with:

```
1513162160,,ui,message, amazon-ebs: A new version of /boot/grub/menu.lst is available%!(PACKER_COMMA) but the version installed
1513162160,,ui,message, amazon-ebs: currently has been locally modified.
1513162160,,ui,message, amazon-ebs:
1513162160,,ui,message, amazon-ebs: 1. install the package maintainer's version
1513162160,,ui,message, amazon-ebs: 2. keep the local version currently installed
1513162160,,ui,message, amazon-ebs: 3. show the differences between the versions
1513162160,,ui,message, amazon-ebs: 4. show a side-by-side difference between the versions
1513162160,,ui,message, amazon-ebs: 5. show a 3-way difference between available versions
1513162160,,ui,message, amazon-ebs: 6. do a 3-way merge between available versions (experimental)
1513162160,,ui,message, amazon-ebs: 7. start a new shell to examine the situation
1513162160,,ui,message, amazon-ebs:
```

The solution is:
`sudo DEBIAN_FRONTEND=noninteractive apt-get -y -o Dpkg::Options::=\"--force-confdef\" -o Dpkg::Options::=\"--force-confold\" upgrade"`

Which was the initial fix proposed for this bug at:
https://askubuntu.com/questions/146921/how-do-i-apt-get-y-dist-upgrade-without-a-grub-config-prompt/147079#147079
back in 2012

Interesting, how this reappeared in 2017.