Make the worker MPM shutdown and restart cleanly. This also

cleans up some race conditions, and gets the worker using
pools more cleanly.

Submitted by:	[Aaron Bannert <aaron@clove.org>]


git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/trunk@90635 13f79535-47bb-0310-9956-ffa450edef68