OZG-4453 log as severe

ozgcloud-elasticsearch-operator/src/main/java/de/ozgcloud/operator/OzgCloudElasticsearchService.java

 package de.ozgcloud.operator;
 
 import java.util.Objects;
+import java.util.logging.Level;
 
 import org.apache.commons.collections.MapUtils;
 import org.springframework.stereotype.Component;
@@ -130,7 +131,7 @@ public class OzgCloudElasticsearchService {
 				log.info("create successful.");
 			}
 		} catch(Exception e) {
-			log.info("Certificate secret creation failed: " + e);
+			log.log(Level.SEVERE, "Certificate secret creation failed: " + e);
 			throw e;
 		}
 	}