Description of problem:

By putting the version in the path to the DTDs, it makes it difficult for
programs to consistently find the location of the dtd when generating docs. Some
apps work around this by pulling the dtd from the network, but this doesn't work
in the Fedora Extras buildsystem where we don't have network access.

The obvious workaround would be to create symlinks alongside the fully versioned
path, for example:

/usr/share/sgml/docbook/xml-dtd-4.2-1.0-27/docbookx.dtd ->
/usr/share/sgml/docbook/xml-dtd-4.2/docbookx.dtd

Then, applications looking for the 4.2 dtd can specify it, but not have to
hardcode the version.