Migrate perchild to the new lock API, and clean up some of the logic

surrounding the FD passing.  This doesn't work yet, but it is getting
closer.  Currently, the problem is that we don't correctly read the data
from the socket so that it can be passed to the correct child.


git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/trunk@94357 13f79535-47bb-0310-9956-ffa450edef68