Spark-on-YARN missing user customizations of hadoop config

In my change to fix SPARK-22372, I removed some code that allowed user customizations of hadoop configs to take effect. Notably, these lines in YarnSparkHadoopUtil:

 override def newConfiguration(conf: SparkConf): Configuration = {
   val hadoopConf = new YarnConfiguration(super.newConfiguration(conf))
   hadoopConf.addResource(Client.SPARK_HADOOP_CONF_FILE)
   hadoopConf
 }

The addResource call is now missing so user configs are ignored (only the NM config is used).