Adapt ensure-dirs to accomodate the additional permissions and files

Please note that this can and will be improved over time. There are discussions
about automated file generation of ensure-dirs so we can _really_ keep all the
permissions and file ownerships in one place. Because right now they are all
in this file _and_ on every WriteFile call.

Signed-off-by: René Nussbaumer <rn@google.com>
Reviewed-by: Michael Hanselmann <hansmi@google.com>