I wasn't correctly sourcing the key; it has to come from hostvars as
it is in a different play on different hosts. This fixes it.
We also need to not have the base roles overwrite the authorized_keys
file each time. The key we provision can only run a limited script
that wraps "vos release".
Unfortunately our gitops falls down a bit here because we don't have
full testing for the AFS servers; put this on the todo list :) I have
run this manually for testing.
Change-Id: I0995434bde7e43082c01daa331c4b8b268d9b4bc