apache/spark — pull request #779 by andrewor14 (2014-05-14 23:00:45+00:00)
Title: [SPARK-1838] Spark on YARN throws exception for local mode

The following happens:
```
Caused by: java.lang.Exception: Yarn Local dirs can't be empty
at org.apache.spark.executor.Executor.getYarnLocalDirs(Executor.scala:133)
at org.apache.spark.executor.Executor.(Executor.scala:68)
```

However, the environment variable `YARN_LOCAL_DIRS` isn't even used for local mode. This PR ensures that the exception is not thrown for this mode.