Updating README.md with gerrit URL
Updating README.md with gerrit URL

Change-Id: Ie1804e9c52c5b46f2c15a4ccb3821a9b4347d6aa

zhihu/puppet-cdh,zhihu/puppet-cdh,wikimedia/operations-puppet-cdh4,wikimedia/operations-puppet-cdh4,2014/puppet-cdh,deric/puppet-cdh,wikimedia/operations-puppet-cdh4,2014/puppet-cdh,deric/puppet-cdh,tomahc/puppet-cdh,tomahc/puppet-cdh,deric/puppet-cdh