'repl' is already allocated in the request pool by 'construct_host_header()' the line just before.

So this is safe to use the 'apr_table_setn' variant in order to save a few bytes of memory.

git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/trunk@1777593 13f79535-47bb-0310-9956-ffa450edef68