Remove unixd_detach function, because it is provided by APR as ap_detach.

This also modifies the ap_detach function to look like unixd_detach.
Finally all calls to unixd_detach are changed to ap_detach.


git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/trunk@85635 13f79535-47bb-0310-9956-ffa450edef68