Can it be this simple?  No, probably not, but this fast-hack will get
  us going again for a while.

  We are currently rejecting some internal file_sub_req()'s in the
  translate phase.  I don't like this hack because of risks it potentially
  exposes, but for today, if we have a filename - and we are a subrequest,
  then let it fly without further mapping.  This allows us to serve up
  the default "/" request (run through mod_dir->mod_negotiation->mod_mime)
  without a 400 error.  The right solution is to set up some traps and
  escapes for the subreq mechanism, possibly with a subreq translate hook,
  and drop the URI entirely for these cases.


git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/trunk@90847 13f79535-47bb-0310-9956-ffa450edef68