The ubuntu, and ubuntu-minimal elements both make use of a common set
of environment settings to determine the distribution name.
The ubuntu-minimal element also does a few extra things which would
appear to apply to both sets and bring in extra architecture support.
As such, these are included in the common element.
This intends to be part of a series of patches which will eventually
create a new element to build a minimal ubuntu-systemd-container
element which can be used for lxc/nspawn containers.
Change-Id: Ia4e620f7d3fa6215484a8d218cea2f28bd1ffaee
Deploying many nodes with the generated image shouldn't have the same
/etc/machine-id so clearing it and letting systemd generate a new
id upon first boot seems to be the best way to achieve this.
Change-Id: I73d0577d31464521b3989312fd9d982a1312a268
Closes-bug: 1707526
Closes-bug: 1672461
