merge these fixes from 2.1-dev:

  *) worker MPM: Fix a problem which could cause httpd processes to
     remain active after shutdown.  [Jeff Trawick]

  *) Unix MPMs: Shut down the server more quickly when child processes are
     slow to exit.  [Joe Orton, Jeff Trawick]

Reviewed by: stoddard, striker


git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/branches/2.0.x@159470 13f79535-47bb-0310-9956-ffa450edef68