fix context samples bean id (#414)

diff --git a/dubbo-samples-context/src/main/java/org/apache/dubbo/samples/context/ContextConsumer.java b/dubbo-samples-context/src/main/java/org/apache/dubbo/samples/context/ContextConsumer.java
index cfa2eb8..36739e0 100644
--- a/dubbo-samples-context/src/main/java/org/apache/dubbo/samples/context/ContextConsumer.java
+++ b/dubbo-samples-context/src/main/java/org/apache/dubbo/samples/context/ContextConsumer.java
@@ -26,7 +26,7 @@
     public static void main(String[] args) {
         ClassPathXmlApplicationContext context = new ClassPathXmlApplicationContext("spring/dubbo-context-consumer.xml");
         context.start();
-        ContextService contextService = context.getBean("demoService", ContextService.class);
+        ContextService contextService = context.getBean("contextService", ContextService.class);
 
         String hello = contextService.sayHello("world");
         System.out.println("result: " + hello);