[SPARK-4078] New FsPermission instance w/o FsPermission.createImmutable in eventlog

By default, Spark builds its package against Hadoop 1.0.4 version. In that version, it has some FsPermission bug (see [HADOOP-7629] (https://issues.apache.org/jira/browse/HADOOP-7629) by Todd Lipcon). This bug got fixed since 1.1 version. By using that FsPermission.createImmutable() API, end-user may see some RPC exception like below (if turn on eventlog over HDFS).  Here proposes a quick fix to avoid certain exception for all hadoop versions.
```
Exception in thread "main" java.io.IOException: Call to sr484/10.1.2.84:54310 failed on local exception: java.io.EOFException
        at org.apache.hadoop.ipc.Client.wrapException(Client.java:1150)
        at org.apache.hadoop.ipc.Client.call(Client.java:1118)
        at org.apache.hadoop.ipc.RPC$Invoker.invoke(RPC.java:229)
        at $Proxy6.setPermission(Unknown Source)
        at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
        at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
        at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
        at java.lang.reflect.Method.invoke(Method.java:597)
        at org.apache.hadoop.io.retry.RetryInvocationHandler.invokeMethod(RetryInvocationHandler.java:85)
        at org.apache.hadoop.io.retry.RetryInvocationHandler.invoke(RetryInvocationHandler.java:62)
        at $Proxy6.setPermission(Unknown Source)
        at org.apache.hadoop.hdfs.DFSClient.setPermission(DFSClient.java:1285)
        at org.apache.hadoop.hdfs.DistributedFileSystem.setPermission(DistributedFileSystem.java:572)
        at org.apache.spark.util.FileLogger.createLogDir(FileLogger.scala:138)
        at org.apache.spark.util.FileLogger.start(FileLogger.scala:115)
        at org.apache.spark.scheduler.EventLoggingListener.start(EventLoggingListener.scala:74)
        at org.apache.spark.SparkContext.<init>(SparkContext.scala:324)
```

Author: Grace <jie.huang@intel.com>

Closes #2892 from GraceH/eventlog-rpc and squashes the following commits:

58ea038 [Grace] new FsPermission Instance w/o FsPermission.createImmutable

core/src/main/scala/org/apache/spark/scheduler/EventLoggingListener.scala

@@ -142,7 +142,7 @@ private[spark] object EventLoggingListener extends Logging {
   val SPARK_VERSION_PREFIX = "SPARK_VERSION_"
   val COMPRESSION_CODEC_PREFIX = "COMPRESSION_CODEC_"
   val APPLICATION_COMPLETE = "APPLICATION_COMPLETE"
-  val LOG_FILE_PERMISSIONS = FsPermission.createImmutable(Integer.parseInt("770", 8).toShort)
+  val LOG_FILE_PERMISSIONS = new FsPermission(Integer.parseInt("770", 8).toShort)
 
   // A cache for compression codecs to avoid creating the same codec many times
   private val codecMap = new mutable.HashMap[String, CompressionCodec]