Fix flogger format string

Change-Id: I765aaa0eb0869385c5d2aee6db1d28eb614836ae

src/main/java/com/gerritforge/gerrit/globalrefdb/validation/RefUpdateValidator.java

diff --git a/src/main/java/com/gerritforge/gerrit/globalrefdb/validation/RefUpdateValidator.java b/src/main/java/com/gerritforge/gerrit/globalrefdb/validation/RefUpdateValidator.java
index 09ac89c..c86a346 100644
--- a/src/main/java/com/gerritforge/gerrit/globalrefdb/validation/RefUpdateValidator.java
+++ b/src/main/java/com/gerritforge/gerrit/globalrefdb/validation/RefUpdateValidator.java
@@ -230,10 +230,8 @@
               Project.nameKey(projectName), refPair.compareRef, refPair.putValue);
     } catch (GlobalRefDbSystemError e) {
       logger.atWarning().withCause(e).log(
-          "Not able to persist the data in Zookeeper for project '{}' and ref '{}', message: {}",
-          projectName,
-          refPair.getName(),
-          e.getMessage());
+          "Not able to persist the data in Zookeeper for project '%s' and ref '%s', message: %s",
+          projectName, refPair.getName(), e.getMessage());
       throw e;
     }