Backport TraceEnable option, correcting RFC violation by mod_proxy as this
  now drops any proxied TRACE request which tries to pass a body, unless
  the user explicitly forces 'TraceEnable extended'.

  Per colm; removed \n's from error_notes, docs coming next.

Reviewed by: jimj, colm


git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/branches/2.0.x@290502 13f79535-47bb-0310-9956-ffa450edef68