Change Jetty version from 9.2.16.v20160414 to 9.3.3.v20150827.

## What changes were proposed in this pull request?
This patch changes Jetty version from 9.2.16.v20160414 to 9.3.3.v20150827, in order to match the Jetty version used in the universe.

## How was this patch tested?
N/A

Author: Reynold Xin <[email protected]>

Closes apache#48 from rxin/rxin-jetty-version.

Author: rxin

core/src/main/scala/org/apache/spark/ui/JettyUtils.scala

@@ -27,8 +27,8 @@ import scala.xml.Node
 
 import org.eclipse.jetty.server.{Request, Server, ServerConnector}
 import org.eclipse.jetty.server.handler._
+import org.eclipse.jetty.server.handler.gzip.GzipHandler
 import org.eclipse.jetty.servlet._
-import org.eclipse.jetty.servlets.gzip.GzipHandler
 import org.eclipse.jetty.util.component.LifeCycle
 import org.eclipse.jetty.util.thread.QueuedThreadPool
 import org.json4s.JValue

pom.xml

@@ -137,7 +137,7 @@
     <derby.version>10.12.1.1</derby.version>
     <parquet.version>1.8.1</parquet.version>
     <hive.parquet.version>1.6.0</hive.parquet.version>
-    <jetty.version>9.2.16.v20160414</jetty.version>
+    <jetty.version>9.3.3.v20150827</jetty.version>
     <javaxservlet.version>3.1.0</javaxservlet.version>
     <chill.version>0.8.0</chill.version>
     <ivy.version>2.4.0</ivy.version>