Remove cloud-init

[cgwalters]

I did a test build locally, set up a mock metadata service that
had a small Ignition config, and it worked.

[cgwalters]

Removed:
  cloud-init-0.7.9-24.el7.x86_64
  cloud-utils-growpart-0.29-2.el7.noarch
  pyserial-2.6-6.el7.noarch
  python-babel-0.9.6-8.el7.noarch
  python-jinja2-2.7.2-2.el7.noarch
  python-jsonpatch-1.2-4.el7.noarch
  python-jsonpointer-1.9-2.el7.noarch
  python-markupsafe-0.11-10.el7.x86_64
  python-prettytable-0.7.2-3.el7.noarch

[dustymabe]

/lgtm

[cgwalters]

Succeeds #88