HDDS-1080. Ozonefs Isolated class loader should support FsStorageStatistics.

Contributed by Elek, Marton.

hadoop-ozone/ozonefs/src/main/java/org/apache/hadoop/fs/ozone/FilteredClassLoader.java

@@ -53,6 +53,8 @@ public class FilteredClassLoader extends URLClassLoader {
     delegatedClasses.add("org.apache.hadoop.fs.ozone.OzoneClientAdapter");
     delegatedClasses.add("org.apache.hadoop.fs.ozone.BasicKeyInfo");
     delegatedClasses.add("org.apache.hadoop.fs.ozone.OzoneFSOutputStream");
+    delegatedClasses.add("org.apache.hadoop.fs.ozone.OzoneFSStorageStatistics");
+    delegatedClasses.add("org.apache.hadoop.fs.ozone.Statistic");
     delegatedClasses.add("org.apache.hadoop.fs.Seekable");
     this.delegate = parent;
     systemClassLoader = getSystemClassLoader();