apache/spark — pull request #1684 by li-zhihui (2014-07-31 07:27:04+00:00)
Title: Fix conflict between code and doc in YarnClientSchedulerBackend.scala

Doc say: system properties override environment variables.
https://github.com/apache/spark/blob/master/yarn/common/src/main/scala/org/apache/spark/scheduler/cluster/YarnClientSchedulerBackend.scala#L71

But code is conflict with it.