Comment 9 for bug 1505839

This really seems to be an issue with packer, and not the Ubuntu installer.

May I suggest a better alternative. Instead of using packer why not use the ubuntu cloud images available
http://cloud-images.ubuntu.com/

or use virt-install and the netboot installers a.la.
virt-install \
        --connect qemu:///system \
        --virt-type kvm \
        --name demo \
        --ram 2048 \
        --disk size=10 \
        --graphics vnc \
        -l ftp://ftp.utexas.edu/pub/ubuntu/dists/trusty/main/installer-amd64/ \
       --os-variant ubuntutrusty

The ubuntu text mode installer is a pretty pristine fork from debian, and as such I don't think we should be fixing this in Ubuntu.