ZOOKEEPER-927. there are currently 24 RAT warnings in the build -- address directly or via exclusions (Michi Mutsuzaki via phunt)

git-svn-id: https://svn.apache.org/repos/asf/zookeeper/trunk@1611846 13f79535-47bb-0310-9956-ffa450edef68
ignore encoding warning
fix concurrent atomic
fix volatile increment