[SPARK-13423][HOTFIX] Static analysis fixes for 2.x / fixed for Scala 2.10

## What changes were proposed in this pull request?

Fixes compile problem due to inadvertent use of `Option.contains`, only in Scala 2.11. The change should have been to replace `Option.exists(_ == x)` with `== Some(x)`. Replacing exists with contains only makes sense for collections. Replacing use of `Option.exists` still makes sense though as it's misleading.

## How was this patch tested?

Jenkins tests / compilation

(If this patch involves UI changes, please attach a screenshot; otherwise, remove this)

Author: Sean Owen <sowen@cloudera.com>

Closes #11493 from srowen/SPARK-13423.2.

core/src/main/scala/org/apache/spark/ui/jobs/JobsTab.scala

@@ -29,7 +29,7 @@ private[ui] class JobsTab(parent: SparkUI) extends SparkUITab(parent, "jobs") {
   val operationGraphListener = parent.operationGraphListener
 
   def isFairScheduler: Boolean =
-    jobProgresslistener.schedulingMode.contains(SchedulingMode.FAIR)
+    jobProgresslistener.schedulingMode == Some(SchedulingMode.FAIR)
 
   attachPage(new AllJobsPage(this))
   attachPage(new JobPage(this))

core/src/main/scala/org/apache/spark/ui/jobs/StagesTab.scala

@@ -34,7 +34,7 @@ private[ui] class StagesTab(parent: SparkUI) extends SparkUITab(parent, "stages"
   attachPage(new StagePage(this))
   attachPage(new PoolPage(this))
 
-  def isFairScheduler: Boolean = progressListener.schedulingMode.contains(SchedulingMode.FAIR)
+  def isFairScheduler: Boolean = progressListener.schedulingMode == Some(SchedulingMode.FAIR)
 
   def handleKillRequest(request: HttpServletRequest): Unit = {
     if (killEnabled && parent.securityManager.checkModifyPermissions(request.getRemoteUser)) {

sql/core/src/main/scala/org/apache/spark/sql/execution/ui/SQLListener.scala

@@ -335,7 +335,7 @@ private[spark] class SQLHistoryListener(conf: SparkConf, sparkUI: SparkUI)
       taskEnd.taskInfo.accumulables.flatMap { a =>
         // Filter out accumulators that are not SQL metrics
         // For now we assume all SQL metrics are Long's that have been JSON serialized as String's
-        if (a.metadata.contains(SQLMetrics.ACCUM_IDENTIFIER)) {
+        if (a.metadata == Some(SQLMetrics.ACCUM_IDENTIFIER)) {
           val newValue = new LongSQLMetricValue(a.update.map(_.toString.toLong).getOrElse(0L))
           Some(a.copy(update = Some(newValue)))
         } else {