Empty ini files not outputting correctly

[Joshua Harlow]

It appears empty configuration files, with values being set on them do not actually result in those values then being output. This appears to be a feature/bug of iniparse and configparser and how it handles the DEFAULT section whereby if the DEFAULT section is not present in the initial document that subsequent modifications to the DEFAULT sections keys and values will not cause a new DEFAULT section to be created (and then output). Since nova.conf.sample recently disappeared and now the handling of this returns an empty string (without a DEFAULT section) we need to add logic that creates a DEFAULT section if it is not present in the initial document to ensure that the keys/values we add/remove/set are actually adjusted and output correctly.

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.openstack.org/85796

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/85796
Committed: https://git.openstack.org/cgit/stackforge/anvil/commit/?id=6f47cd92e81126cd888a3d72d81dc967ecc611c1
Submitter: Jenkins
Branch: master

commit 6f47cd92e81126cd888a3d72d81dc967ecc611c1
Author: Joshua Harlow <email address hidden>
Date: Mon Apr 7 12:25:34 2014 -0700

    Fix empty ini files not including DEFAULT section

    Empty files and subsequent modification by adding, removing,
    setting and changing keys then outputting those files seems
    to cause iniparse to ignore the whole DEFAULT section. To fix
    this modify the write() function to correctly output the DEFAULT
    section when it exists (but does not exist in the read data).

    Fixes bug 1303968

    Change-Id: I1b4133bc6f876e9e5e39045f46054db13bd4634f