Skip warnings we can't avoid

git-svn-id: https://svn.apache.org/repos/asf/poi/trunk@896866 13f79535-47bb-0310-9956-ffa450edef68

src/java/org/apache/poi/poifs/dev/POIFSViewable.java

@@ -54,7 +54,7 @@ public interface POIFSViewable
      * @return an Iterator; may not be null, but may have an empty
      * back end store
      */
-
+    @SuppressWarnings("unchecked")
     public Iterator getViewableIterator();
 
     /**

src/java/org/apache/poi/poifs/filesystem/DirectoryNode.java

@@ -410,7 +410,7 @@ public class DirectoryNode
      * @return an Iterator; may not be null, but may have an empty
      * back end store
      */
-
+    @SuppressWarnings("unchecked")
     public Iterator getViewableIterator()
     {
         List components = new ArrayList();