Interestingly, after upgrading to Ubuntu Utopic Unicorn, the build script I made for Docker.io fails during the Go build. Something inside the Utopic minimal install is not being liked by the Go build script, so for now, you will have to force the LXC container to use Trusty instead.

lxc-create -n Ubuntu -t ubuntu -- --release trusty --auth-key /home/user/.ssh/id_rsa.pub