Merge r1537812 (partially) and r1542069.

* r1537812, r1542069
  Use a real URI parser in mod_dontdothat
  Justification:
    Current parser is busted.
  Votes:
    +1: breser, philip, stefan2


git-svn-id: https://svn.apache.org/repos/asf/subversion/branches/1.8.x@1542073 13f79535-47bb-0310-9956-ffa450edef68