Remove all of the calls to functions like "ap_popenf". These functions were

moved down to APR, but they are being removed.  They are not portable, and
were only moved down for backwards compatability.  With this change, they can
be safely removed, which is the next commit on it's way.
Submitted by:  Ryan Bloom and Paul Reder


git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/trunk@83879 13f79535-47bb-0310-9956-ffa450edef68