DUBBO-282 将连接报警检查的时间间隔从默认5分钟改为15分钟。

此参数的作用是在设定时间内，重连失败不报警。

git-svn-id: http://code.alibabatech.com/svn/dubbo/trunk@1289 1a56cb94-b969-4eaa-88fa-be21384802f2

dubbo-common/src/main/java/com/alibaba/dubbo/common/Constants.java

@@ -256,7 +256,7 @@ public class Constants {
 
     public static final String  SHUTDOWN_TIMEOUT_KEY               = "shutdown.timeout";
 
-    public static final int     DEFAULT_SHUTDOWN_TIMEOUT           = 1000 * 60 * 5;
+    public static final int     DEFAULT_SHUTDOWN_TIMEOUT           = 1000 * 60 * 15;
 
     public static final String  TIMESTAMP_KEY                      = "timestamp";