The RHEL7 version of Anaconda only allows .service units to be used with
the kickstart services command. Update the documentation, examples, and
tests to reflect this.
Related: rhbz#1718473
This adds support for the optional blueprint section [customizations].
Use it like this:
[customizations]
hostname = yourhostnamehere
[[customizations.sshkey]]
user = root
key = root user key
