Upgrade to Jetty 9.3.19.v20170502

Closes spring-projectsgh-9177

Author: wilkinsona

spring-boot-dependencies/pom.xml

@@ -107,7 +107,7 @@
 		<jedis.version>2.8.2</jedis.version>
 		<jersey.version>2.23.2</jersey.version>
 		<jest.version>2.0.4</jest.version>
-		<jetty.version>9.3.18.v20170406</jetty.version>
+		<jetty.version>9.3.19.v20170502</jetty.version>
 		<jetty-jsp.version>2.2.0.v201112011158</jetty-jsp.version>
 		<jetty-el.version>8.0.33</jetty-el.version>
 		<jms-api.version>1.1-rev-1</jms-api.version>