重构 ServiceBean 的 isDelay 方法，使其更符合语义 (apache#2686)

* Refactor method isDelay of ServiceBean to fix the wrong meaning of the method

* Remove unnecessary method isDelay of ServiceBean

dubbo-config/dubbo-config-spring/src/main/java/org/apache/dubbo/config/spring/ServiceBean.java

@@ -107,23 +107,14 @@ public Service getService() {
 
     @Override
     public void onApplicationEvent(ContextRefreshedEvent event) {
-        if (isDelay() && !isExported() && !isUnexported()) {
+        if (!isExported() && !isUnexported()) {
             if (logger.isInfoEnabled()) {
                 logger.info("The service ready on spring started. service: " + getInterface());
             }
             export();
         }
     }
 
-    private boolean isDelay() {
-        Integer delay = getDelay();
-        ProviderConfig provider = getProvider();
-        if (delay == null && provider != null) {
-            delay = provider.getDelay();
-        }
-        return supportedApplicationListener && (delay == null || delay == -1);
-    }
-
     @Override
     @SuppressWarnings({"unchecked", "deprecation"})
     public void afterPropertiesSet() throws Exception {
@@ -251,7 +242,7 @@ && getInterface() != null && getInterface().length() > 0
                 setPath(beanName);
             }
         }
-        if (!isDelay()) {
+        if (!supportedApplicationListener) {
             export();
         }
     }