Stop using HARD_SERVER_LIMIT/HARD_THREAD_LIMIT all over the place

and instead use the mpm query function to retrieve those limits and
use those dynamically-retrieved values when walking the scoreboard.


git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/trunk@92510 13f79535-47bb-0310-9956-ffa450edef68