SLING-5484 - add debug log for default user

git-svn-id: https://svn.apache.org/repos/asf/sling/trunk@1728484 13f79535-47bb-0310-9956-ffa450edef68
diff --git a/src/main/java/org/apache/sling/serviceusermapping/impl/ServiceUserMapperImpl.java b/src/main/java/org/apache/sling/serviceusermapping/impl/ServiceUserMapperImpl.java
index fbb3465..e0e8220 100644
--- a/src/main/java/org/apache/sling/serviceusermapping/impl/ServiceUserMapperImpl.java
+++ b/src/main/java/org/apache/sling/serviceusermapping/impl/ServiceUserMapperImpl.java
@@ -375,7 +375,7 @@
             }
         }
 
-        // finally, fall back to default user
+        log.debug("No mapping found, fallback to default user [{}]", this.defaultUser);
         return this.defaultUser;
     }