Remove second prefix line. Only need it documented once in the same file.

(closes issue #11472)
Reported by: eserra
Patches:
      http.conf.sample.diff uploaded by eserra (license 45)


git-svn-id: https://origsvn.digium.com/svn/asterisk/trunk@91171 65c4cc65-6c06-0410-ace0-fbb531ad65f3