Update sample configuration to match what are now the defaults for the prefix.

(closes issue #12838, related to issue #12198)
 Reported by: pabelanger
 Patches: 
       http.conf.diff2 uploaded by pabelanger (license 224)


git-svn-id: https://origsvn.digium.com/svn/asterisk/trunk@125191 65c4cc65-6c06-0410-ace0-fbb531ad65f3