Copied from kafka 0.8.1.1 https://git-wip-us.apache.org/repos/asf?p=kafka.git;a=blob;f=core/src/main/scala/kafka/log/LogConfig.scala
Borrowed from kafka 0.8.1.1, adapted to use curator framework https://git-wip-us.apache.org/repos/asf?p=kafka.git;a=blob;f=core/src/main/scala/kafka/admin/PreferredReplicaLeaderElectionCommand.scala