[SPARK-2904] Remove non-used local variable in SparkSubmitArguments

Author: Kousuke Saruta <sarutak@oss.nttdata.co.jp>

Closes #1834 from sarutak/SPARK-2904 and squashes the following commits:

38e7d45 [Kousuke Saruta] Removed non-used variable in SparkSubmitArguments

core/src/main/scala/org/apache/spark/deploy/SparkSubmitArguments.scala

@@ -219,7 +219,6 @@ private[spark] class SparkSubmitArguments(args: Seq[String]) {
 
   /** Fill in values by parsing user options. */
   private def parseOpts(opts: Seq[String]): Unit = {
-    var inSparkOpts = true
     val EQ_SEPARATED_OPT="""(--[^=]+)=(.+)""".r
 
     // Delineates parsing of Spark options from parsing of user options.