Use Logger's built-in string formatting

Change-Id: I1b8b6a3f7ce188a88b5a0969ccc739e1f2aa977f
diff --git a/src/main/java/com/googlesource/gerrit/plugins/readonly/DisableCommandInterceptor.java b/src/main/java/com/googlesource/gerrit/plugins/readonly/DisableCommandInterceptor.java
index 447c86b..a6105ff 100644
--- a/src/main/java/com/googlesource/gerrit/plugins/readonly/DisableCommandInterceptor.java
+++ b/src/main/java/com/googlesource/gerrit/plugins/readonly/DisableCommandInterceptor.java
@@ -42,7 +42,7 @@
       return in;
     }
 
-    log.warn("Disabling command: " + in);
+    log.warn("Disabling command: {}", in);
     return pluginName + " disable";
   }
 }