ZooKeeper 3.6.0 release.

[maven-release-plugin] copy for tag release-3.6.0-4

[maven-release-plugin] copy for tag release-3.6.0-3

ZooKeeper 3.5.7 release.

ZooKeeper 3.5.7-rc2 release

ZooKeeper 3.5.7-rc1 release.

[maven-release-plugin] copy for tag release-3.6.0-2

ZooKeeper 3.5.7-rc0 release.

[maven-release-plugin] copy for tag release-3.6.0-1

[maven-release-plugin] copy for tag release-3.6.0-0