Fix the forking/killing logic in the threaded MPM. The problem we were

seeing with the server eating itself wasn't because we were comparing
the idle_thread_count and min/max spare servers wrong.  It was because
we were counting idle_thread_count incorrectly.  This fixes that problem.


git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/trunk@89495 13f79535-47bb-0310-9956-ffa450edef68