These variables need to be delimited with {} or they will conflict with

other variables in the same namespace with a shorter prefix substring.
How did this ever work before? I ran into this while testing some of
the recent layout-fixing patches.


git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/trunk@93577 13f79535-47bb-0310-9956-ffa450edef68