Add a note about case-sensitivity to the windows platform docs.

Partially in response to the disputed vulnerability:
http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2006-4110


git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/trunk@433005 13f79535-47bb-0310-9956-ffa450edef68