Make clean, distclean, and extraclean consistently according to the

Gnu makefile guidelines.

Submitted by: Justin Erenkrantz <jerenkrantz@ebuilt.com>
Reviewed by:  Roy Fielding


git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/trunk@88809 13f79535-47bb-0310-9956-ffa450edef68