resolve conflicting netty3 versions fixes T50885

apparently zookeeper was pulling in netty 3.2.2 from old maven
coordinates. This caused us to use older, buggier 3.2.2 netty, but
also who knows what else complications from imperfect class
overrides. eg. if newer netty has a class not in old netty, and
somewhere our code uses that as an entry point, then it will be
running newer code, but might call classes running older code.

Most notably, this will hopefully address hanging mqworker or mss
processes that get stuck trying to call "releaseExternalResources"
on their netty servers. This is a known netty bug that was fixed
a long time ago, and will hopefully just go away by instead using
the expected version.