Preparing for release 3.5.0

git-svn-id: https://svn.apache.org/repos/asf/zookeeper/trunk@1615237 13f79535-47bb-0310-9956-ffa450edef68
Preparing for 3.6 development

git-svn-id: https://svn.apache.org/repos/asf/zookeeper/trunk@1615240 13f79535-47bb-0310-9956-ffa450edef68