Adding boilerplate errata/CVS instructions

[David Malcolm]

Attached is a file that supplies boilerplate instructions for reporting
errors/patches with a document.

Also attached is a patch to my Stateless Linux tutorial which pulls in
the file and uses it, with the various sub-entities given sane
definitions.

You can see a usage of this file in an unofficial copy of that tutorial,
located here:
http://people.redhat.com/dmalcolm/stateless/stateless-linux-HOWTO-
en/#errata-tip

I propose adding the first file as "fedora-docs/common/errata-en.xml"

Any thoughts/rewrites?  Perhaps the heading should read "About This
Document" instead?

Dave Malcolm