Fix my recent change for sending large files via the http server. This code

*must* write the file to the FILE *, and not the raw fd.  Otherwise, it breaks
TLS support.

Thanks to rizzo for catching this!


git-svn-id: https://origsvn.digium.com/svn/asterisk/trunk@72738 65c4cc65-6c06-0410-ace0-fbb531ad65f3