Merge r1028797, r1028799 from trunk:

  Add a note about LimitRequest* and name-based vhosts as followup on PR#7741

  make the name-based vhost note a warning based on offline discussion with Rich


git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/branches/2.0.x@1028803 13f79535-47bb-0310-9956-ffa450edef68