A small update was made to 4.4.0-96.119 that dropped the
initramfs-tools dependency from the kernel [1]. This had the
unfortunate affect of removing the initramfs from ubuntu-minimal and
making it unbootable, since we specify the root device via LABEL=.
Add the package explicitly alongside the kernel.
Also, small fix to pass unit tests
[1] https://bugs.launchpad.net/ubuntu/+source/linux-azure/+bug/1700972
Change-Id: I57a0f08cd5e082ecdf8dba0ab34fb3062c50836d
