ZOOKEEPER-1715. Upgrade netty version (Sean Bridges via michim)


git-svn-id: https://svn.apache.org/repos/asf/zookeeper/branches/branch-3.4@1550902 13f79535-47bb-0310-9956-ffa450edef68
ZOOKEEPER-1837. Fix JMXEnv checks (potential race conditions) (Germán Blanco via fpj)


git-svn-id: https://svn.apache.org/repos/asf/zookeeper/branches/branch-3.4@1550923 13f79535-47bb-0310-9956-ffa450edef68
ZOOKEEPER-1839. Deadlock in NettyServerCnxn (Rakesh R via michim)


git-svn-id: https://svn.apache.org/repos/asf/zookeeper/branches/branch-3.4@1551112 13f79535-47bb-0310-9956-ffa450edef68
ZOOKEEPER-1622. session ids will be negative in the year 2022 (Eric Newton via phunt)

git-svn-id: https://svn.apache.org/repos/asf/zookeeper/branches/branch-3.4@1551118 13f79535-47bb-0310-9956-ffa450edef68