[Merge] lp:~mterry/livecd-rootfs/system-user into lp:livecd-rootfs

[Michael Terry]

I also add the user to the nopassswdlogin group, since the current image doesn't ask for a password either.  Once we switch to lightdm, the user will need to be in that group to allow for that.
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https://code.launchpad.net/~mterry/livecd-rootfs/system-user/+merge/179784
Your team Ubuntu Core Development Team is requested to review the proposed merge of lp:~mterry/livecd-rootfs/system-user into lp:livecd-rootfs.