Fix brokenness when ThreadsPerChild is higher than the built-in

limit.  We left ap_threads_per_child at the higher value which
led to segfaults when doing certain scoreboard operations.


git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/trunk@89375 13f79535-47bb-0310-9956-ffa450edef68