[Merge] ~davidkrauser/livecd-rootfs/+git/livecd-rootfs:ubuntu/master into livecd-rootfs:ubuntu/master

[Robert C Jennings]

Review: Needs Fixing

Your comment "If running a custom kernel, we should try to boot without an initramfs" could do more to make explicit that GRUB_FORCE_PARTUUID is being used as the mechanism for initramfs-less boot, as this is not an obvious mapping.  In fact, you should just drop a comment in 
${mountpoint}/etc/default/grub.d/40-force-partuuid.cfg" for the end-user to that effect; otherwise the behavior for an end-user is a inscrutable.

Your commit messages for this change needs to explain why we're changing this.  Specifically that this had been enabled by default for all cloud images yet there is no expectation that generic images with the linux-generic kernel would be able to boot without an initramfs.  Therefore, the initramfs-less boot, which is a boot optimization, should only be applied where we know it could work for users and provide an improved boot experience; images with custom-tuned kernels are candidates for that.
-- 
https://code.launchpad.net/~davidkrauser/livecd-rootfs/+git/livecd-rootfs/+merge/386913
Your team Ubuntu Core Development Team is requested to review the proposed merge of ~davidkrauser/livecd-rootfs/+git/livecd-rootfs:ubuntu/master into livecd-rootfs:ubuntu/master.