Comment 1 for bug 1373964

also might make sense even to just have it available as a command:
  curtin write-files
then the user could explicitly call it at a different stage fairly easily.

We also need to be clear about when it runs. Jtv asked me if he could use it to write /etc/network/interfaces, and i'm not actually sure if tha twould stick or if the configure networking would overwrite it with OUTPUT_NETWORK_INTERFACES.