Fix links and update content in introduction. Update page content to

reflect that mod_ssl in 2.0 doesn't actually provide the most of the
backwards-compat hooks; leave it as a guide for migration.


git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/trunk@103830 13f79535-47bb-0310-9956-ffa450edef68