httpd.exp is a generated file, and therefore, it is generated into the

build directory, not the source directory.  When we go to use it, we
have to look in the build dir for it.


git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/trunk@91142 13f79535-47bb-0310-9956-ffa450edef68