ENG-5609 leader appointer deletes failded partitions recursively
ENG-5609 fix wrong usage fo VoidCallback in ZKUtils.asyncDeleteRecursevely
Merge branch 'master' into ENG-5609
Merge pull request #1020 from VoltDB/ENG-5609

This is marked as for ENG-5609 but it is actually for ENG-5607. Leader appointer needs to delete failed partitions recursively.
ENG-5502: Minor tweaks.
Merge remote-tracking branch 'origin/master' into ENG-5502-client-java6