mod_disk_cache now turns off sendfile support if 'EnableSendfile off'

is defined globally.

Reviewed by: Ruediger Pluem, Issac Goldstand, Niklas Edmundsson



git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/branches/2.2.x@746552 13f79535-47bb-0310-9956-ffa450edef68