Check an alternative return value for when a file or directory does not exist....

Check an alternative return value for when a file or directory does not exist.  Previously this would return a forbidden on the documentation website for any URL ending in .html.


git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/trunk@219879 13f79535-47bb-0310-9956-ffa450edef68