Fixed NPE if origin is unset (#2100)

spring-cloud-netflix-hystrix-dashboard/src/main/java/org/springframework/cloud/netflix/hystrix/dashboard/HystrixDashboardConfiguration.java

@@ -135,6 +135,7 @@ public class HystrixDashboardConfiguration {
 				response.getWriter()
 						.println(
 								"Required parameter 'origin' missing. Example: 107.20.175.135:7001");
+				return;
 			}
 			origin = origin.trim();