add clean up method for closing rabbitmq connection

fixed eiffel-remrem-publish/issues/23

src/main/java/com/ericsson/eiffel/remrem/publish/helper/RMQHelper.java

@@ -10,6 +10,7 @@
 import org.springframework.stereotype.Component;
 
 import javax.annotation.PostConstruct;
+import javax.annotation.PreDestroy;
 import java.io.IOException;
 import java.util.ArrayList;
 import java.util.List;
@@ -41,6 +42,17 @@
         }
     }
 
+    @PreDestroy
+    public void cleanUp() throws IOException {
+        log.info("RMQHelper cleanUp ...");
+        if (rabbitConnection!=null){
+            rabbitConnection.close();
+            rabbitConnection = null;
+        } else {
+            log.warn("rabbitConnection is null when cleanUp");
+        }
+    }
+
     public void send(String routingKey, String msg) throws IOException {
         giveMeRandomChannel()
             .basicPublish(exchangeName, routingKey, MessageProperties.BASIC, msg.getBytes());