[SPARK-16868][WEB UI] Fix executor be both dead and alive on executor ui.

## What changes were proposed in this pull request?
In a heavy pressure of the spark application, since the executor will register it to driver block manager twice(because of heart beats), the executor will show as picture show:
![image](https://cloud.githubusercontent.com/assets/7404824/17467245/c1359094-5d4e-11e6-843a-f6d6347e1bf6.png)

## How was this patch tested?
NA

Details in: [SPARK-16868](https://issues.apache.org/jira/browse/SPARK-16868)

Author: huangzhaowei <carlmartinmax@gmail.com>

Closes #14530 from SaintBacchus/SPARK-16868.

core/src/main/scala/org/apache/spark/storage/StorageStatusListener.scala

@@ -77,6 +77,10 @@ class StorageStatusListener(conf: SparkConf) extends SparkListener {
       val maxMem = blockManagerAdded.maxMem
       val storageStatus = new StorageStatus(blockManagerId, maxMem)
       executorIdToStorageStatus(executorId) = storageStatus
+
+      // Try to remove the dead storage status if same executor register the block manager twice.
+      deadExecutorStorageStatus.zipWithIndex.find(_._1.blockManagerId.executorId == executorId)
+        .foreach(toRemoveExecutor => deadExecutorStorageStatus.remove(toRemoveExecutor._2))
     }
   }