Make sure we don't overwrite an existing DocRoot and CGI scripts

on "make install".

Submitted by: Ralf S. Engelschall (based on Jim's initial patch)
Reviewed by: Jim Jagielski, Ralf S. Engelschall


git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/branches/1.3.x@80997 13f79535-47bb-0310-9956-ffa450edef68