Improve docstrings from previous documentation patch

[Matt Wagner]

I submitted https://review.openstack.org/#/c/83577/ a while back. It was a misguided attempt to add documenation for configuration options.

We decided that it made much more sense to just make the text in the sample configuration file more helpful, which is basically what I did in that patch -- except I moved it to a static file instead.

It'd be valuable to move the descriptions from that file to the docstrings that generate the sample config file, and to also look into the "FIXME" questions I had there.

[Matt Wagner (matt-wagner)]

Unassigning myself for now, though I will tackle this if no one else does. If someone gets to it before me, feel free.

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.openstack.org/130642

[Dmitry Tantsur (divius)]

Hi all! Judging by the (seemingly abandoned) patch I believe after numerous changes to our config this bug is no longer valid. Please reopen with explanation if you feel otherwise.

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.openstack.org/174164

[Ruby Loo (rloo)]

This patch: https://review.openstack.org/174164 includes changes based on the documentation from https://review.openstack.org/#/c/83577/ and from the previous patch above https://review.openstack.org/130642.

(I had contacted Jon Grimm in March, to see if he was going to finish 130642 and he said that if he didn't do it, I was welcome to finish it. I'm not sure now, why I created a new patch instead of finishing his. Maybe because I wanted to start from scratch with the original documentation.)

[OpenStack Infra (hudson-openstack)]

Change abandoned by Ruby Loo (<email address hidden>) on branch: master
Review: https://review.openstack.org/130642
Reason: Am abandoning this patch because https://review.openstack.org/174164 includes these changes.

Jon, I know we discussed that I could finish this patch, but I ended up doing a separate patch. Hope you don't mind. Not sure why now, although maybe it was cuz this needed to be rebased and I wanted to start from scratch, making changes as I looked through Matt's original document.

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/174164
Committed: https://git.openstack.org/cgit/openstack/ironic/commit/?id=5b40b113333734034669c1de0d0eb758f3393797
Submitter: Jenkins
Branch: master

commit 5b40b113333734034669c1de0d0eb758f3393797
Author: Ruby Loo <email address hidden>
Date: Thu Apr 16 00:22:26 2015 +0000

    Update some config option's help strings

    Some config option's help strings are updated based on the
    documentation/feedback in a previous patch that attempted
    to document the config options, but we decided that it would
    be better to update the help in the configs themselves:
        https://review.openstack.org/#/c/83577/

    Change-Id: Ied2a4d69b735e919ab0597ac8d53df5dcd2a0ff6
    Closes-Bug: 1324169