Stop copying file names that we get from apr_file_t's and apr_dir_t's.

Stop copying file names that we get from apr_file_t's and apr_dir_t's.
We copy the data when we store it in the structures, we can just return
a pointer from there, and use const data.  This puts the onus back on
Apache to copy the data if it needs to modify it.

git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/trunk@87592 13f79535-47bb-0310-9956-ffa450edef68