yep. too bad there are so many places in the code where this problem

appears.  i feel like we ought to take the opposite approach and guarantee
that r->filename is never NULL, but oh well.  we've gone down this path
instead, so this is clearly a correct fix.


git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/branches/APACHE_2_0_BRANCH@101466 13f79535-47bb-0310-9956-ffa450edef68