Fix comment to allow modules using the new authz scheme to work on Win32.

* mod_auth.h: Fix up blurb on how to retrieve ap_satisfies to match what
  mod_authz_core and friends use which does work on Windows.


git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/trunk@490054 13f79535-47bb-0310-9956-ffa450edef68