If exceptions occur in startup, storage node will exit. Avoid a misguide.

skywalking-storage-center/skywalking-storage/src/main/java/com/a/eye/skywalking/storage/Main.java

@@ -65,6 +65,7 @@ public class Main {
             logger.error("SkyWalking storage server start failure.", e);
         } finally {
             server.stop();
+            System.exit(-1);
         }
     }