It is not sufficient to reset the file pointer before each call to ap_send_fd. A...

It is not sufficient to reset the file pointer before each call to ap_send_fd.  A better solution
is to make certain that only apr_sendfile() will be used to send content with a cached file handle.
This assumes that apr_sendfile() should not rely on the position of the file pointer. I suspect that
sendfile implementations that rely on the position of the file pointer are broken and we should not
use sendfile on those platforms.

git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/trunk@87654 13f79535-47bb-0310-9956-ffa450edef68