Fixed new factory configuration. It was non optional which in result

will not work if the factory comes from another source, e.g. cloud
foundry.

Signed-off-by: Kai Zimmermann <kai.zimmermann@bosch-si.com>

hawkbit-dmf-amqp/src/main/java/org/eclipse/hawkbit/amqp/AmqpConfiguration.java

@@ -59,6 +59,7 @@ public class AmqpConfiguration {
     private ConnectionFactory rabbitConnectionFactory;
 
     @Configuration
+    @ConditionalOnMissingBean(ConnectionFactory.class)
     protected static class RabbitConnectionFactoryCreator {
 
         @Autowired