Fix broken compile for platforms with sendfile() -- As Graham says: Looks like...

Fix broken compile for platforms with sendfile() -- As Graham says: Looks like this code hasn't built in the SENDFILE case for a while.

git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/trunk@470455 13f79535-47bb-0310-9956-ffa450edef68