Upgrade to Jetty 9.2.15.v20160210

Upgrade to Jetty 9.2.15 and replace use of API that was deprecated
and changed to throw an UnsupportedOperationException in the same
release.

Closes gh-5218

spring-boot-dependencies/pom.xml

@@ -98,7 +98,7 @@
 		<jdom2.version>2.0.6</jdom2.version>
 		<jedis.version>2.7.3</jedis.version>
 		<jersey.version>2.22.2</jersey.version>
-		<jetty.version>9.2.14.v20151106</jetty.version>
+		<jetty.version>9.2.15.v20160210</jetty.version>
 		<jetty-jsp.version>2.2.0.v201112011158</jetty-jsp.version>
 		<jmustache.version>1.11</jmustache.version>
 		<joda-time.version>2.8.2</joda-time.version>

spring-boot/src/main/java/org/springframework/boot/context/embedded/jetty/JettyEmbeddedServletContainerFactory.java

 /*
- * Copyright 2012-2015 the original author or authors.
+ * Copyright 2012-2016 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -661,8 +661,7 @@ public class JettyEmbeddedServletContainerFactory
 		public HandlerWrapper createGzipHandler(Compression compression) {
 			GzipHandler gzipHandler = new GzipHandler();
 			gzipHandler.setMinGzipSize(compression.getMinResponseSize());
-			gzipHandler.setMimeTypes(
-					new HashSet<String>(Arrays.asList(compression.getMimeTypes())));
+			gzipHandler.addIncludedMimeTypes(compression.getMimeTypes());
 			if (compression.getExcludedUserAgents() != null) {
 				gzipHandler.setExcluded(new HashSet<String>(
 						Arrays.asList(compression.getExcludedUserAgents())));