[Merge] lp:~rcj/livecd-rootfs/trusty-proposed_ubuntu-cpc into lp:~ubuntu-core-dev/livecd-rootfs/trusty-proposed

[Robert C Jennings]

This depends on https://code.launchpad.net/~rcj/ubuntu/+source/live-build/+git/live-build/+ref/feature/support_livecd-rootfs_ubuntu-cpc commits.  There's no tree for trusty live-build so I made use of the usd-import-team tree.
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https://code.launchpad.net/~rcj/livecd-rootfs/trusty-proposed_ubuntu-cpc/+merge/324682
Your team Ubuntu Core Development Team is requested to review the proposed merge of lp:~rcj/livecd-rootfs/trusty-proposed_ubuntu-cpc into lp:~ubuntu-core-dev/livecd-rootfs/trusty-proposed.