Added SignalLogger to HistoryServer.

This was omitted in #1260. @aarondav

Author: Reynold Xin <[email protected]>

Closes #1300 from rxin/historyServer and squashes the following commits:

af720a3 [Reynold Xin] Added SignalLogger to HistoryServer.

Author: rxin

core/src/main/scala/org/apache/spark/deploy/history/HistoryServer.scala

@@ -27,7 +27,7 @@ import org.apache.spark.{Logging, SecurityManager, SparkConf}
 import org.apache.spark.deploy.SparkHadoopUtil
 import org.apache.spark.ui.{WebUI, SparkUI, UIUtils}
 import org.apache.spark.ui.JettyUtils._
-import org.apache.spark.util.Utils
+import org.apache.spark.util.{SignalLogger, Utils}
 
 /**
  * A web server that renders SparkUIs of completed applications.
@@ -169,10 +169,11 @@ class HistoryServer(
  *
  * This launches the HistoryServer as a Spark daemon.
  */
-object HistoryServer {
+object HistoryServer extends Logging {
   private val conf = new SparkConf
 
   def main(argStrings: Array[String]) {
+    SignalLogger.register(log)
     initSecurity()
     val args = new HistoryServerArguments(conf, argStrings)
     val securityManager = new SecurityManager(conf)