Small edits on help strings

These were initially noted during import into the manuals at
https://review.openstack.org/67502

Fixes include rework of text, missing or extra spaces, wrong
capitalization and no sentence style capitalization.

A hacking check has been added that tests that all config options
start with a capital letter.

Change-Id: I0a1c333bbb3a812932d3972a7403f94da0bff341
Co-Authored-By: Daniel Berrange <berrange@redhat.com>
Co-Authored-By: Diane Fleming <diane.fleming@rackspace.com>
Merge "Small edits on help strings"