Don't setup the uncaught exception handler in local mode.

This avoids unit test failures for Spark streaming.

    java.util.concurrent.RejectedExecutionException: Task org.apache.spark.streaming.JobManager$JobHandler@38cf728d rejected from java.util.concurrent.ThreadPoolExecutor@3b69a41e[Terminated, pool size = 0, active threads = 0, queued tasks = 0, completed tasks = 14]
	at java.util.concurrent.ThreadPoolExecutor$AbortPolicy.rejectedExecution(ThreadPoolExecutor.java:2048)
	at java.util.concurrent.ThreadPoolExecutor.reject(ThreadPoolExecutor.java:821)
	at java.util.concurrent.ThreadPoolExecutor.execute(ThreadPoolExecutor.java:1372)
	at org.apache.spark.streaming.JobManager.runJob(JobManager.scala:54)
	at org.apache.spark.streaming.Scheduler$$anonfun$generateJobs$2.apply(Scheduler.scala:108)
	at org.apache.spark.streaming.Scheduler$$anonfun$generateJobs$2.apply(Scheduler.scala:108)
	at scala.collection.mutable.ResizableArray$class.foreach(ResizableArray.scala:60)
	at scala.collection.mutable.ArrayBuffer.foreach(ArrayBuffer.scala:47)
	at org.apache.spark.streaming.Scheduler.generateJobs(Scheduler.scala:108)
	at org.apache.spark.streaming.Scheduler$$anonfun$1.apply$mcVJ$sp(Scheduler.scala:41)
	at org.apache.spark.streaming.util.RecurringTimer.org$apache$spark$streaming$util$RecurringTimer$$loop(RecurringTimer.scala:66)
	at org.apache.spark.streaming.util.RecurringTimer$$anon$1.run(RecurringTimer.scala:34)