Handle the vals that never used

In XORShiftRandom.scala, use val "million" instead of constant "1e6.toInt".
Delete vals that never used in other files.

Author: WangTao <barneystinson@aliyun.com>

Closes #565 from WangTaoTheTonic/master and squashes the following commits:

17cacfc [WangTao] Handle the unused assignment, method parameters and symbol inspected by Intellij IDEA
37b4090 [WangTao] Handle the vals that never used

core/src/main/scala/org/apache/spark/network/SecurityMessage.scala

@@ -106,7 +106,6 @@ private[spark] class SecurityMessage() extends Logging {
    * @return BufferMessage
    */
   def toBufferMessage: BufferMessage = {
-    val startTime = System.currentTimeMillis
     val buffers = new ArrayBuffer[ByteBuffer]()
 
     // 4 bytes for the length of the connectionId

core/src/main/scala/org/apache/spark/partial/GroupedMeanEvaluator.scala

@@ -61,7 +61,6 @@ private[spark] class GroupedMeanEvaluator[T](totalOutputs: Int, confidence: Doub
     } else if (outputsMerged == 0) {
       new HashMap[T, BoundedDouble]
     } else {
-      val p = outputsMerged.toDouble / totalOutputs
       val studentTCacher = new StudentTCacher(confidence)
       val result = new JHashMap[T, BoundedDouble](sums.size)
       val iter = sums.entrySet.iterator()

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

@@ -118,11 +118,9 @@ object BlockFetcherIterator {
       })
       bytesInFlight += req.size
       val sizeMap = req.blocks.toMap  // so we can look up the size of each blockID
-      val fetchStart = System.currentTimeMillis()
       val future = connectionManager.sendMessageReliably(cmId, blockMessageArray.toBufferMessage)
       future.onSuccess {
         case Some(message) => {
-          val fetchDone = System.currentTimeMillis()
           val bufferMessage = message.asInstanceOf[BufferMessage]
           val blockMessageArray = BlockMessageArray.fromBufferMessage(bufferMessage)
           for (blockMessage <- blockMessageArray) {

core/src/main/scala/org/apache/spark/util/random/XORShiftRandom.scala

@@ -91,7 +91,7 @@ private[spark] object XORShiftRandom {
     val xorRand = new XORShiftRandom(seed)
 
     // this is just to warm up the JIT - we're not timing anything
-    timeIt(1e6.toInt) {
+    timeIt(million) {
       javaRand.nextInt()
       xorRand.nextInt()
     }

examples/src/main/java/org/apache/spark/examples/JavaLogQuery.java

@@ -75,7 +75,6 @@ public final class JavaLogQuery {
 
   public static Tuple3<String, String, String> extractKey(String line) {
     Matcher m = apacheLogRegex.matcher(line);
-    List<String> key = Collections.emptyList();
     if (m.find()) {
       String ip = m.group(1);
       String user = m.group(3);

examples/src/main/java/org/apache/spark/examples/JavaTC.java

@@ -85,7 +85,7 @@ public final class JavaTC {
         }
     });
 
-    long oldCount = 0;
+    long oldCount;
     long nextCount = tc.count();
     do {
       oldCount = nextCount;

examples/src/main/java/org/apache/spark/examples/sql/JavaSparkSQL.java

@@ -23,7 +23,6 @@ import java.util.List;
 import org.apache.spark.api.java.JavaRDD;
 import org.apache.spark.api.java.JavaSparkContext;
 import org.apache.spark.api.java.function.Function;
-import org.apache.spark.api.java.function.VoidFunction;
 
 import org.apache.spark.sql.api.java.JavaSQLContext;
 import org.apache.spark.sql.api.java.JavaSchemaRDD;