fix(configdrive): Always run after OEM and ec2 metadata.

A workaround for https://github.com/coreos/coreos-cloudinit/issues/86

Longer term cloudinit needs to be fixed to not corrupt the system when
multiple config sources are being used. We've pretty much gotten this
far without this coming up because most configs don't conflict so badly.
Merge pull request #87 from marineam/hack

fix(configdrive): Always run after OEM and ec2 metadata.