debug log + unset in the log msg

Author: virajjasani

hadoop-tools/hadoop-aws/src/main/java/org/apache/hadoop/fs/s3a/S3AFileSystem.java

@@ -1006,7 +1006,7 @@ protected RequestFactory createRequestFactory() {
             STORAGE_CLASS, storageClassConf);
       }
     } else {
-      LOG.info("Empty storage class property {}; falling back to default storage class",
+      LOG.debug("Unset storage class property {}; falling back to default storage class",
           STORAGE_CLASS);
     }