mod_ssl:

- document the SSLStapling* directives (code committed in
  r829619 for 2.2.3, see PR 43822)
- add SSLCARevocationCheck to the list of configuration changes
  in the 2.4 upgrade notes.


git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/trunk@1173755 13f79535-47bb-0310-9956-ffa450edef68