add child_terminate() function

PR:
Obtained from:
Submitted by:	Doug MacEachern
Reviewed by:	Alexei Kosut, Jim Jagielski, Rob Hartill


git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/branches/1.3.x@79173 13f79535-47bb-0310-9956-ffa450edef68