remove codereview-proxy.wm.org from DNS

RT #6146

< ^d> codereview-proxy is a relic from mayflower days and probably could've died sooner.
<@RobH> then lets kill it
< ^d> When we needed a way to get svn from europe to us :)

Change-Id: Ic6e5280729ea21e88165d6ba4b1af69de77ede24