[Merge] ~cjwatson/livecd-rootfs:xenial/exclude-makedev into livecd-rootfs:ubuntu/xenial

[Adam Conrad]

Review: Approve

Confirmed that the hand-rolled xenial chroots didn't have makedev.  +1 from me on landing this, commit away.
-- 
https://code.launchpad.net/~cjwatson/livecd-rootfs/+git/livecd-rootfs/+merge/372869
Your team Ubuntu Core Development Team is subscribed to branch livecd-rootfs:ubuntu/xenial.